I have been part of a group for four years now, going on five, and I've pretty much stuck with that group. It's not out of being a dick or anything, it's just what I am used to. When (or if, at this rate) that group falls apart, I dunno. I might keep roleplaying, or I might put all that energy into attempting to publish stuff.

That all being said, my favorite type of RP is the kind that takes place in fantasy worlds that are not extremely magic-laden. I only like advanced RP's because I want to be able to practice writing skills (casual doesn't really help in that if you are used to advanced). Though I mostly have done NRP's, I am comfortable with any RP that allows you a hefty amount of breathing room when it comes to character count and how much you can make up on your own.