Are you paying Out of Pocket or on a dining plan? That will change my answer, as to me many of the buffets are WAY overpriced, but can be well worth one TS credit.
If on the dining plan:
MK = Ohana, or in second... Crystal Palace. Crystal Palace has enough choices to please anyone and is conveniently located.
EP = Coral Reef (if sitting right up by the tanks). This one is hit or miss for some. Always been a hit for us, but we order the Chef's sustainable catch, the seared Mahi Mahi, or the strip steak and are always pleased. Can't beat the view.
HS = Cape May's Cafe (take friendship boat from HS to Beach Club. Easy 15 minute trip). Wonderful location and lot's of seafood and other options on the buffet
AK = Yak and Yeti or Tusker House. Yak and Yeti - Steak and Shrimp, and the miso salmon are both excellent
If paying OOP:
MK = The Wave at the Contemporary.
EP = Via Napoli
HS = Sci-fi or Mama Melrose
AK = Yak and Yeti
Dan