I voted MGM. We always go, but really is only because of RnRC and ToT. Take away those two rides, and MGM wouldn't be much, IMHO.
MK would be second. I like the other parks because they are never as crowded as MK.
If you like ToT/RnRC, and are on time budget -- just do those two rides and leave.
D'oh! As usual I voted before I read the question! I thought we were voting for our favorite and went for Epcot. Don't skip Epcot! Tough question, but I think maybe MGM Studios if I was forced to pick.
Whoops... I didn't read the poll. I voted for MGM thinking it was for my favorite park. Take one away from MGM and add one onto Epcot.... I could definitely skip that (and have!!).