I voted for Epcot, but it would have to be my really extended family. I would enjoy really low crowds, but I don't know, not having other people around also having a good time wouldn't be as good.
Not that I like crowds, but sometimes observing someone else getting the magic can really make it magical for us.
It would, however, be nice to have REAL front of the line access to Mission:Space and Test Track (especially Test Track, MS seems more efficient for FP holders, but I've never ridden TT with a FP without still waiting in line for at least a half hour).
Kungaloosh!
Mort.