MK - Columbia Harbor House or Pecos Bill are our favorites, though I really do miss the fixings bar at Pecos.
AK - Satu'li Canteen is probably our favorite QS on WDW property
EP - La Cantina de San Agel and Sunshine Seasons are both pretty good, but we usually just hit up the festival booths
HS - Backlot Express is pretty good - it's basic theme park food, but it's executed well
Most of the resort QS places we've tried are pretty basic, but we absolutely love Geyser Point, and in addition to the table seating it has a walkup / takeout window.
Also, for ice cream treats the Beaches and Cream walkup window is great.