I mainly play new base classes from supplements for some reason. My last few characters have been a psion, a psychic warrior, and a warlock. Playing the psion now, I kind of wish I had been playing a wizard instead, though. I'm always out of power points, and I find myself looking longingly at the wizard's spells slots per day table.
My next character is probably going to be a duskblade, so it looks like I'm on track to keep playing classes from outside the core rules. I'm also considering playing a non-multi-classed fighter using the new feats from PHII to see if they really make the fighter a viable 20-level class.