I also stuck with the brutes in K1 and K2, but that's because the story was the same no matter which character class you chose. I like wielding a lightsaber so I favored the melee classes.
However, since the story is different for each class in TOR, I am going to go with the Sith Inquisitor. Just at first glance it sounds much more interesting to me. Hunting down ancient Sith treasures, having an apprentice, etc; plus I truly don't know at this point whether I want to try to make light-side choices as an inquisitor or stay on the dark path. It will really be on a case-by-case basis and that sounds exciting to me.