I love Supernatural. For me, it's the best Sci-Fi/Fantasy series currently in production, and I've been watching it since Episode 1. They bridge the plot lines between seasons so well, infuse new characters without ever truly "jumping the shark", and the humor is just awesome.
To compare to other series out there:
I tend to think of the first three seasons at least as kind of a "freelance x-files", and even some episodes after. Just instead of using UFO's as a long term story ark, there are a few other main antagonists. (Note: no significant UFO content in this series, if that's what you're looking for.)
I'm Not much of a Buffy the Vampire Slayer fan, but I know a lot of people who liked that and like this. On the other hand, I find Supernatural to be a lot grittier, better special effects, and less comic-book like than any of the episodes of Buffy I've seen. So don't take one for granted as the other.
For those that are looking more for a "scare the crap out of me, can't go to bed" type series, I have to say it's a 50/50 shot. On one hand my girlfriend will not watch this without me there and spending the night, so for some it will have that effect. On the other hand it's been rare that I've had trouble sleeping.

Sorry for anyone who's looking for comments on this season in particular, I like the series enough I'm currently in the habit of just buying them all so I can re-watch in future years... except I will comment that Castiel became of my favorite sci-fi characters ever. :-P

Though most on this forum have given the show kudos for the angels versus demons storyline, I have to give the writers their "props" for finally bringing Dean, wonderfully played by Jensen Ackles, to the forefront of the season. The character gets to mature, realizing his place in the ongoing battle against the forces of evil as well as being Sam's (Jared Padalecki) protector, even when the younger brother is toying with his own inner "demon". Ackles shines in "I Know What You Did Last Summer", "The Rapture", the season opener "Are You There, God? It's Me, Dean Winchester", and the season-ending "Lucifer Rising". Why he nor Padalecki have not received Emmy nominations is a further indictment against the decision makers of The Academy of Television Arts and Sciences.

Fine acting is also provided by Jim Beaver as the dependable and Johnny-on-the-spot Bobby Singer, Misha Collins as Castiel the angel, Genevieve Cortese as the "is-she-a-good-demon-or-a-bad-demon" Ruby, Robert Wisdom as Uriel, and Julie McNiven as Anna. The casting of "The X-Files" Mitch Pileggi as the Winchester boys' grandfather in "In the Beginning", as is the father-son team of John and Michael Rubenstein, along with character greats Barry Bostwick and Richard Libertini in "Criss Angel is a Douche Bag," another outstanding episode.

"After School Special" features younger versions of Sam and Dean, played convincingly by Colin Ford and Brock Kelly, respectively. The installment also makes a commentary on the cruelty of high school students against each other.

"Monster Movie" brilliantly pays homage to the classic horror films of the 30's and 40's, complete with period music, costuming, and black and white filming.

As a whole, the season features excellent writing, top-knotch direction, scoring, and some true thrills. Because of the intensity of the latter, the writers separate the chills with some comedic and satirical dialog, many delivered by sardonic bliss by Ackles.

The compilation features audio commentary on two episodes, deleted scenes, and a "gag" reel that's not very funny, just a chance to see the guys mug for the camera.

This is a show that only gets better with time. Every season the writers find new and creative ways to keep us coming back. We all knew that Dean would not stay in hell forever, and I was very curious how he would get out. Never did I imagine that in addition to all the demons and ghosts we would have angels too.
This season the main story line revolves around the book of revelations in the bible. The demons are breaking the 66 seals nessasary to raise Lucifer from hell, and the angels are supposedly trying to stop it. It turns out that while Dean was in hell, he broke the first seal and put everything in motion.
Dean, Sam and Bobby are working their hardest, along side the angel Castiel, to prevent the seals from breaking, but are not haveing much luck. It turns out that some of the angels want lucifer to rise in order to force a battle that they are convinced that they can win.
The entire season is not completly dedicated to the angels and demons storylines. It would not be Supernatural if it did not include a few episodes mixed in that make us laugh. My 2 favorites are Wishfull Thinking, and Yellow Fever. Wishfull Thinking involves residents of a town whose every wish is being granted via a wishing well in a chinese resturant. The only problem is that the wishes go bad. Dean test it out, and wishes for a sandwich, only to get food poisoning from it, and a little girl wishes for her teddy bear to become real and life size, only to get life size teddy that drinks all day, steals porn, and tries to commit suicide because he feels that life has no meaning. Yellow fever involves a new twist on the tradional ghost story. Dean and Sam head to a town where healthy residents are droping dead of heart attacks. It turns out that they are infected with ghost sickness, which makes them afraid of everything, extremely paranoid, and will die after 3 days unless they scare the ghost into exercising itself. Dean winds up infected and there is an extemely entertaining moment of him running down the street in fear of his life from a small dog with a pink bow in its hair.
The season finale does a grerat job of wrapping up the season and setting up the next season. We also find out the full truth about Ruby, and she gets what has been long coming to her. The only real sour note is the ongoing storyline of Sam being addicted to demon blood. I thought that was a little to crazy even for this show.
The dvd extras are a little thin, but I recommend that everyone pick up this season.

Oh, boy. I love this show, and I had trouble respecting this episode.

It's a disjointed, quickly-thrown-together, crappy episode. It hurts to say that about one of my favorite shows, but there you go.

Negatives:
1) the Ruby character--oy. Where to begin. Will she ever really be more than a prop? I don't know. But she isn't more than a prop in this episode. She feeds Sam some lines that help shape later bits in the episode, but otherwise, she does a lot of screaming and bleeding and not much else.
2) Castiel and Uriel--they are wasted here (although Castiel actually is a plus in some ways--see below). They come for Anna, ostensibly to kill her, and they of course encounter resistance from the menfolk, who just don't get that these angels aren't all warm and cuddly and. . .well, angelic. No, they have a mission, and sometimes the stuff they gotta do is horrible. Why is this surprising to the Winchester men? I dunno. Anyway, these two angels get short shrift here, and it's annoying that Castiel, in particular, gets used that way. Also--what's up with the whole Alastair-can't-be-killed thing? Does that mean he's better than an angel of the Lord, or what? Utter confusion. So--these guys get used in the plot line, and all that happens as a result is that the viewer gets utterly confused. Perfect.
3) The whole plot line is convoluted and filled with happenings that don't make much sense. Pamela comes back to help Anna figure out what's really in her head that she can't remember, but that comes from left field. And almost everything that happens here seems disconnected. Maybe it's that so much is left kind of unexplained, and the show won't be on again until January, so eh? I'm confused, unsatisfied, and basically left to be so for another two months. Fantastic.

Good stuff:
1) Jensen Ackles. He's been kicking acting butt for two years or more now, and he just gets better and better. This guy knows how to make Dean vulnerable, and his willingness to just put Dean Winchester out there and let him be human and flawed and in deep, deep pain, with all the acting challenges that comes with--well, kudos to you, Jensen Ackles. You are superb. From the way your face can show childlike glee (think the "Mystery Spot" episode) to the way your eyes can actually go blurry and your face seem to crumple in on itself from guilt and self-loathing. Oh, yeah. The last scene in this episode is a perfect example of what I mean. Every muscle twitch, the way you refuse to stop those tears--a long time coming, they are--to just overflow, and the way every single emotion is just. . .THERE. Awesome. Someone give this man an Emmy.
2) Castiel--like Jensen Ackles, Misha. . .what's his last name? Huh. Can't remember. Anyway, the guy who plays Castiel. He can convey so much with just a subtle shift in expression. At one point, when Anna realizes that Dean has given her up to Uriel and Castiel in order to save Sam from death or a quick toss into the pit of Hell, she turns to Dean and tells him she understands and forgives him. The camera pans to Castiel a couple of times, and the longing in his eyes (for the human emotions that angels aren't supposed to feel or enjoy having) as well as the respect he has for Dean and the decisions he makes at risk of his own sanity and happiness--all there on this guy's face and in his eyes. Good job here, too.

Those are the only two positives I can see in this episode, but they were enough to keep me from giving it one or two stars.

Hopefully the new episodes in January will return with the quality of the first four or so of this season.

Again--someone give Mr. Ackles an Emmy or a People's Choice or something. Wow.

The familial chemistry of the Winchester brothers is back and harder than ever to beat for entertainment in this season. This go round, each actor continues to bring a wide range of human emotion to his role and is man to the task as the brothers take separate paths.

The conflict between brothers, demons and angels escalates this season. Episode 1 begins with Dean crawling out of a grave, no longer a captive in hell, but uninformed as to why. He quickly tracks down Sam and the two are off again, fighting, laughing, making choices, and interacting more intensely than ever before. The "Supernatural" mythology introduced in previous seasons continues to develop and, by the end of the season, it's clear that this show could easily go another two seasons (and I hope it does).

The "Monster Movie" and "It's a Terrible Life" episodes are excellent.

(Probably the most bothersome thing about "Supernatural"--and it's not that big of a deal--is when Dean and Sam are working on a ghost case, discover the remains have been cremated and then say something to the effect of, "There must be a lock of hair around or something." I mean, anyone who's ever been alive must have left hair, fingernail clippings and microbes all over the place. . . . Minor gripe.)

And after four seasons, I still don't know who my favorite show-brother is, which (for me) is a strong indication of how well-written and well-acted this TV show really is.

(Not that there's anything wrong with cliffhangers.)

In this one, the Winchester brothers encounter Anna, a woman who is, as Dean points out and I paraphrase, "tuned in to Angel Radio." Anna can hear the angels talking, and she's hearing all this chatter about a coming apocalypse. She also hears a lot about Sam and Dean (aka "THE Dean," a label that makes Dean just a wee bit uncomfortable and makes Sam roll his eyes, since he's not a fave of said angels), and because she can hear these angels, she's become someone the demons want to have in their possession (what better than your own personal "radio" to tell you what God's angels are planning?) and the angels want to kill (what's worse than someone who can reveal all your plans to the dark side?).

The part of this episode that I really want to see expanded out is the encounter Dean has with Alistair, who apparently had a mighty fine time torturing Dean in Hell. Hmmm. . .I want the rest of this story.

As I think I've mentioned in at least one previous review somewhere, Jensen Ackles is kicking acting bohiney this year (he did a mighty fine job last year, too), and it's good that his time in "the pit" is finally being addressed because if anyone can blend angst, humor and soul-crushing pain in one episode, it's Ackles.

Good one!

Supernatural is one of the most interesting and underappreciated series on TV. It combines humor, horror and spiritual themes without being saccharin. Although Christianity is not at all overt in the series, the mindset and stories come from the last several millennia of Christian thinking. Siupernatural makes a statement that dabbling in witchcraft and demonology is dangerous and wrong. The rituals are strongly based on John Dee's enochian work, including the sigil of Amareth. Incredibly well done. I don't understand how they hooked up with a technical advisor that was so well versed. My only complaint is that a coujple of demons are named "Aleister" and "Crowley," which I think is rather uncalled for. Many of the bad guys are named after goetic spirits, which is quite appropriate. As a member of the OTO, I love the use of the unicursal hexagram as the sigil of the "Men of Letters," identified later in the series. This season is the beginning of the time when the series really hit its stride.

With the agonizing cliffhanger of season three's finale, I could not wait to see what the writers had in store for the fans in this season. Straight from the start they had us on the edge of our seats with the return of an uncertain character and the continuation of a great story. To be honest, I was a little worried after watching season 3. I was trying to figure out what they could do to keep me watching this show. The two main actors, Jared Padalecki and Jensen Ackles, really work well together and keep this show fresh this season. I have always been a fan of the supernatural and spiritual warfare. This season really went above and beyond when it came to continuing the story while still giving us fun episodes. The fighting between the heavenly host and the love to hate 'em demons only made me love the direction of this season more. A few well placed plot twists, and even better episode ideas really made this season engaging. I cannot recommend this show enough. If you have not started watching this show yet, now is a great time if not the best time to start tuning in. It is much more interesting if you have followed the whole series since the season premiere is the extention of a cliffhanger, but its still more than interesting enough to start here if you do not want to go back and watch them all.