Plants Vs Zombies 2 looks pretty fantastic. Admittedly, I'm basing that on it being shown off by PopCap, who seem to know exactly what to do - check out that subtitle - in a video describing what's going on the new game. But I think it's fair to say that if the zombie-apocalypse genre ever needed a representative in the puzzle-game department, this should probably be it.
Don't they seem like lovely folk, too? Aw.
Trivia: I mistype this as 'Planets Vs Zombies' every time. Which would be a rather different game.