Top 5 restaurants in EPCOT, that's tough. Like someone else said, you will probably get a "ton" of opinons. In my opinon, they are...
Restaurant Marrakesh
Mitsukoshi's Teppanyaki
Chefs De France
Le Cellier
Biergarten
But like I said, this is my opinon, if you would have asked this same question six months ago the list would probably have been different. There are a couple of restaurants that have recieved really good reviews lately, like Rose and Crown and the Garden Grill. Unfortunately I can't afford to eat everywhere on each trip so I can only comment on what I know first hand.