Buffy the Vampire Slayer is a roleplaying game by Eden Studios based on the television show of the same name. Licensed roleplaying games have a reputation for being almost universally terrible (pick up a copy of the WWF Roleplaying game or Street Fighter 2: The Roleplaying Game to see what I am talking about), but the Buffy RPG is actually pretty good. More than pretty good, it is more along the lines of wonderful.
The game uses the mechanics of Eden Studios' Unisystem, which is the same basic system used in the Angel RPG, All Flesh Must Be Eaten and about a half dozen other games. I have been gaming for years, and I have seen all sorts of systems, but this one really surprised me. The basic system is fairly simple and very fast paced, although it features a variety of combat moves that rivals many games that are far more complex. The system is essentially an opposed roll system that does not have separate damage rolls. But it has one wonderful little quirk that gamemasters have got to love. Only the players roll for things. NPCs, monsters and such always get the same average roll, and it is already built into their stats.
For example, if Buffy is trying to kick a vampire then she would roll her attack and it would go against the vampires defense score. If a vampire was trying to kick Buffy then the vamp's (fixed) attack score would go against a defense roll by Buffy. Meanwhile, if that same vampire was trying to bite an NPC (such as Dawn Summers), then the entire thing would be resolved without rolling any dice at all.
In fact, looking through all the books I had, I could only find a single place where the gamemaster would ever have to roll any dice, and that was a fairly limited situation (has to do with having an NPC make spellcasting mistakes).
Players and NPCs alike all get drama points, which they can use to both change the outcomes of their rolls (or non-rolls), or even to make changes to the story itself. Hero level characters like Buffy Summers and Spike don't get a lot of drama points, but "white hat" characters (like Xander Harris and Cordelia Chase) get a lot more of them. When you need for Dawn to be able to stake a vampire on the first try it is time to use some drama points.
The game uses a point buy system for character creation and distinguishes between hero level characters and "white hat" characters. They technically also mention experienced hero as a character type, but we can ignore that. Hero level characters are people like Buffy Summers, Spike, Angel, Anya, and Riley Finn. Heroes can stand toe to toe with the things that go bump in the night. While "white hat" characters are people like Dawn Summers, Xander Harris, Cordelia Chase, Tara Maclay and most of the random people you might see in the background. This game encourages gaming groups to play groups that include both heroes and "white hats".
Of course the game also explores the option of playing either an all hero game or an all "white hat" game, in case you don't have the kind of players who could handle mixed power levels. I have found that with older experienced players almost everyone will actually be clamoring to play white hats. I thought for sure I would have 4 people fighting over being the slayer with the other two wanting to be vampires, but instead I had three people fighting over being the watcher, with no one wanting to play the Slayer.
The game books are very high quality and contain details on just about every character you ever saw on Buffy, along with a few that you didn't see. The list of books below is complete, and there shouldn't be any more coming out, as Eden Studios no longer has the Buffy license. "Welcome to Sunnydale" and "The Initiative Sourcebook" do not exist, even though the other books mention them in several places (along with a few other books that never came out).
Products in the Buffy RPG line
Buffy the Vampire Slayer Core Rulebook
This is the main book to the game and the only one you really need, although the others are nice as well. It was available in the original version, in a leather bound limited edition (1000 copies made), and it was later revised and rereleased after the show ended. The revised version adds information on seasons six and seven, and makes some slight rules changes to make the rules better match those of the Angel RPG. There is no real need to upgrade if you already have one of the older books.
Slayer's Handbook
This is obviously a word play on the D&D Player's Handbook. It is a nice hardcover that is all about Slayers. It was also available in a leather bound limited edition (1000 copies made, one of which I own).
Monster Smackdown
This hardcover book has statistics for nearly every monster that ever made it on the show, along with some other assorted badness. It was also available in a leather bound limited edition (1000 copies made).
The Magic Box
This is a shorter soft cover book that greatly expands the rather simplistic magic system that was originally presented in the Core Rulebook. This particular title is almost impossible to find at any price. It took me two months to find my copy. The few copies listed on Amazon.com were up to around $100 as of this writing.
Buffy the Vampire Slayer Director's Screen
This is your standard gamemaster screen that comes prepackaged with a few adventures. Highly recommended, not because you will really need the screen, but because it actually has adventures in it. There were no adventure modules released for this game other than the ones that were in the backs of the main rulebooks, which your players probably already read.
Buffy Character Journal
This is fairly self explanatory, at least it only cost $5.