If you're interested in playing a caster, I would recommend Mages, Druids or a Shaman.
Mages are little lot easier than the other two, and are defiantly a Flavor of the Month class with their Never-ending button of Doom. Druids require more involvement, but can be really annoying to deal with when mastered.
Regarding the spec; I know you said you aren't a fan of healing, but when playing a Restoration Druid or Shaman, there is much more to it than healing. You have good damage output, and great mobility for both of those Hybrid classes. A mage's mobility isn't as great, obviously, yet still better than Priest or Warlock.