I'm sticking with my rogue as my main. I've been playing him since day one of my WoW adventures, and I don't plan to stop now. I'm very wary of the class changes (losing so many iconic things from each spec), but I'm eager to give them a shot. My mage is my second choice, and I'll probably be playing at least those two in tandem through the opening months.
I don't know that I have a favourite rogue npc. I hope Jaina and some dragons are around in the mage order hall though. I haven't spoiled any of the mage stuff for myself yet, but I really hope the entire Kirin Tor elite is around.