It really all depends on your tastes. Some places offer something different beyond regular American theme park staples that are really good. But then again, there may be where you want a good old classic burger and fries. So these are my picks. Some are based from personal experience. Others are what I feel a solid majority really like.
MK: Be Our Guest (Vibe I get lunch is better than dinner.), Columbia Harbour House, Plaza Restaurant (Very underrated.), Liberty Tree Tavern
Epcot: Sunshine Seasons, Tangierine Cafe
AK: Flame Tree BBQ, Yak and Yeti
HS: 50s Prime Time Cafe, Mama's Melrose
Downtown Disney (Soon to be renamed Disney Springs): Earl of Sandwich, Wolfgang Puck Express, Raglan Road
Resorts:
AKL: Sanaa, Boma, Jiko
Contemporary: California Grill
Yacht Club: Yachtsmen Steakhouse
Poly: Ohana, Kona Cafe
__________________
"All my life I wonder how it feels to pass a day, not above them but part of them.
And out there living in the sun, give me one day out there, all I ask is one to hold forever. Out there where they all live unaware, what I'd give, what I'd dare, just to live one day out there."