For some reason this game is just not grabbing me. I like the idea, but it just doesn't seem that fantastic. People are raving about it simply because it's Valve and they can apparently do no wrong.
As for the OP, the AI doesn't look that good really. In other videos it looks shockingly bad, more like a HL2 guy or CS:S bot than anything else. I certainly wouldn't want it on a console either!
I'm raving about it because I've always wanted a Zombie game that's good with fast moving enemies, even more so an FPS game.
The addition of co-op is icing on the cake, plus you don't seem to be taking into account the mods that will come out because of Left 4 Dead, I cannot wait for a refined Zombie Mod (Multiplayer) to come out.