CoD maps are never worth it, but somehow every year I manage to talk myself into getting "Elite" or "Premium."
Dig is a fun re-make of a WaW favorite that I never cared for, Frost is a unique map that I enjoy, Pod is a clusterfuck of sorts, interesting style of gameplay, and I still have yet to play the remake of stadium after 50+ games.
As far as zombies, I haven't played.