Ginsu, you summed up my thoughts of JC EXACTLY. The first half was interesting, different (what with that freaky truck, etc), but then it gets real dumb, predictable and the acting and dialogue takes a major nose-dive.
Zombieland... I know it got lots of positive word of mouth, but it isn't THAT great. It's ok. Like 3 out of 5 ok, partly because most (all?) of the best scenes were in the trailer.
Crazies, I have low expectations of. It's an interesting premise, but ultimately it depends on where they go with the premise.