Except it's not an FPS, and even if it were, I can't even think of any zombie FPSes off the top of my head.
Land of the Dead was based off of the film with the same name. It was generic, but decent enough to pirate and play through. Left 4 Dead just came out the other week, and while it follows the new and much lamer "fast zombie" philosophy, it is still damn fun with seven other people. Plenty of older games have promintenly featured zombies even if not being about them. Wolfenstein, Quake, Doom, Doom II, Doom III, Painkiller, etc. Heck, even Half-Life could be counted with those headcrab zombies!

I fear for Resident Evil 5. It may very well be a fun game, but it certainly isn't shaping up to be Resident Evil by any means. Of course, I thought Resident Evil 4 was a little lacking in that regard as well. There was never any "survival" in its horror. You always had plenty of ammo and there were always plenty of enemies. The four or five puzzles in the game weren't even required to progress. It was kind of sad in that regard.