Zombieland is the latest entry in the unlikely "zombie comedy" genre, and while it may not be quite as good as Shaun of the Dead (to my knowledge, the only other entry in the genre), it definitely has its moments.
Aside from the zombies (who differ from any other zombies that I've seen, in that they are really, really fast), there are only four characters in the movie with significant screen time. As Columbus (no names, just hometowns), Jesse Eisenberg looks exactly like the kind of geeky kid who would create a running list of rules to deal with zombies (up to 32 at last count), while Emma Stone (Wichita) and Abigail Breslin (Little Rock) acquit themselves well as sisters who continue to run cons in Zombieland just like they did in the good ol' USA. But the real star of the show, in a great performance, is Woody Harrelson as Tallahassee. All he really wants is to find a twinkie (as he says, "pretty soon lifes little twinkie gauge is gonna go empty"), and kill him some zombies.
The plot, such as it is, isn't much. It's essentially a road film, where the protagonists learn a bit about each other, and try to survive in an inhospitable world where most of those left just want to rip your intestines out and eat them. But the jokes are good, and as you may have heard, there's a great cameo featuring a big, big comedy star that is worth the price of admission all by itself.
So if you only have time to see one zombie comedy this fall, by all means - make it Zombieland.