Damn some people really missed the whole point of this movie. Most people either can't or won't recognize the brilliant satire behind this film (yes Ebert, that means you).
For me, it's just as good as the Chuck Palahniuk book it's based on. The story of this potent work follows a nameless narrator who deals with his sad, lonely existence by becoming addicted to support groups for issues he doesn't have, but fakes, mostly because he finds the attention comforting. His addiction changes from support groups to underground fighting matches with other disaffected men after he meets the kooky soap salesman Tyler Durden. From there, things really start to spiral, but I'm not saying anymore, as part of the joy is experiencing things unfolding for one's self.
The actors do so well with their characters that it's hard to imagine anyone else playing the parts, and not only that, but they become the characters, and you forget that they are really just actors. Fincher's dark and hypnotic style works perfectly with this material, and the editing is also really good.
This movie isn't really about dudes beating each other up in underground fighting venues. It's a critique of masculinity, being marginalized by society, and a major attack against gross materialism and consumerism. This is catharsis at it's finest.
I first saw this when I was a sophomore in high school the same week I first saw Reservoir Dogs and Taxi Driver, and I was never the same after that. Those three films are what lead me to become the rabid film buff that I am, and the rebellious and disaffected nature of the protagonist here really spoke to me, and I found myself really able to identify with a lot of the stuff going on here.
I suppose the film is perhaps a tad overrated, and, unlike the book, the twist doesn't work quite as well, but even then, this film is a powerful, compelling, and amazing work of art. Also, given the content, it really amazes me (still) that this was a mainstream production.
Bottom line, this is a must see.