Consistently hear good things about Flame Tree Barbeque at Animal Kingdom, but haven't managed to talk my wife into trying it. I can't remember -- is all the seating outdoors? That just won't work for me in the summer heat, if so.
I really like having burgers and fries when I'm doing counter service, though Columbia Harbor House does make for a nice change of pace. For the "standard fare," we like Pecos Bill's and/or Cosmic Rays. Both have the toppings bar for burgers and such. Cosmic Rays has the weird setup where you go through different lines for different types of food -- not the best thing when you have varied tastes and small children. On the other hand, Cosmic Ray's also has Sonny Eclipse. The jokes may be intentionally corny, but Kal David, the blues guitarist who performs Sonny's voice, is a well-respected musician and a pretty good singer. There are a few of his numbers I wouldn't mind hearing expanded into full songs.
I can't think of any counter service places at DHS that really set me on fire. Writers Stop near Sci-Fi Dine-In is pretty good, but you won't get a full meal there. Some of the table service places there are good, though.
Epcot -- I like Electric Umbrella. It's essentially Cosmic Rays without Sonny Eclipse (or the weird ordering process), but I like the views you can get -- and remember I usually prefer burgers and fries, especially since Disney now does those pretty well (I remember awful soy burgers in WDW when I was a kid, 30 years ago or so). My wife prefers Sunshine Seasons, and it is pretty darn good, I'll admit.
Scott