Contempo Cafe at The Contemporary is nice if you're doing a MK day. It gets you away from the hustle and bustle for a little bit while serving great food.
Casey's Corner at MK is a classic, but be prepared for some long lines and limited seating.
Cosmic Ray's at MK has really great entertainment for the kids, but average food.
Seconding
@Calee with saying that anything in World Showcase at EP is worth a try. It just depends on your tastes.
ABC Commissary at DHS hasn't ever disappointed. If you go early or late enough (don't go between 12-1:30 p.m.), you can always find seating.
Flame Tree Barbecue and Yak & Yeti are my go-to's for AK. Nice settings and Yak & Yeti has great Asian cuisine for not being in EP.
In summary, if you're eating "American-style" food at any quick service, you're eating the same food. Burgers, nuggets, fries, salads, etc. are all standard across every park. I recommend looking at menus and photos of the restaurants to see what experience you're interested in having.