Gragt
Arcane
I'm not big on tower defense either. I enjoyed Plants vs Zombie for the casual and humourous take on it, and action hybrids like Orcs Must Die! Other than that Revenge of the Titans caught my attention by being very challenging, which is probably why Defense Grid never appealed to me because it looked too easy. Might be wrong as I never tried it, but I saw that people complained more about RotT than GD, so that must be a sign.