I really liked Inquisitor Martyr. It’s sort of Diablo-esque. It certainly isn’t amazing, but I liked the art and story and some of the gameplay. I think you can couch co-op it too.

For RTS, the original Dawn of War is excellent. Especially for the time it came out.

Chaosbane is okay but got old.

I played the first Blood Bowl like crazy on PSP.

And then Space Marine is an excellent story with great kill animations. It can be very difficult as well if you want, if you’re into that.