Well, from everything I've read so far, this one would work quite well.
The System is based around D10 rolls, 9's and higher are successes. You won't use a die higher than a D10, but you'll use D6's, D4's and D8's. (Why the random order I don't know)
There a shitload of customization that you can do with zombies, and if you need to kill off a PC in some gruesome way, what better way than the make some sort of zombie that can actually think and plan?
There's quite a bit of depth in it, and I'm seriously considering running a zombie apocalypse game now.
As for books to go along with a campaign like that. One of the Living, and the Zombie Master Screen would be quite useful I think. Or atlas of the Undead.
I'm planning on getting those quite soon so I can give you a better review of them if you'd like, but from everything I've read so far, It would be all but perfect for a zombie apocalypse. There's even books to have such a thing in dungeons, or in space, in steampunk worlds, or in your standard fantasy setting with ancient zombies capable of casting death magic.