MK-Pecos Bill's. (In the hundreds of times that I have been in the MK, I seem to always find myself in Frontier Land or Adventure Land at lunch time, and go to Pecos Bill's. That is not to say that it is better than the very similar Cosmic Ray's. It just seems that I always end up there)
DHS-ABC Commissary, but only for the Chicken Curry Bowl. Otherwise, I stick with a turkey leg, as most of the CS offerings at DHS are sub-par.
AK-Flame Tree. Always.
Epcot-Again, this has more to do with timing than actual preference, but after spending the morning in FW, we always find ourselves heading to WS around lunch time as the crowds in FW become too much. We start at Mexico and can never seem to get past La Cantina without stopping to eat. Next time I am going to force myself to make it all the way to Germany for brats.
AK - Picnic in the park (I believe this is only offered seasonally now, but when we did it in the fall of '09 it was great and worked out well, and was a great value)
EP - Sunshine Seasons
MK - Probably Pinocchio Village Haus (really, anything but Peco Bills)
HS - Starring Rolls (really, more breakfast/brunch, but we always eat there)
MK Columbia Harbour House followed closely by Pecos Bill
AK Flame Tree Barbeque
DHS Nothing is great but Backlot Express is okay
EC We love eating in the CS international spots in WS.
Sommerfest in Germany for brats and beer, Yakatori House in Japan, Tangerine Cafe in Morrocco, French Bakery in France, Yorkshire County Fish in the UK and Cantina de San Angel in Mexico
Enjoy
MK - Pecos Bill for the do-it-yourself fixings bar that includes sauteed mushrooms
Ep - Sunshine Seasons for hot foods or salads and the ability to sit down indoors to eat; Boulangerie in France for awesome sandwiches and huge choice of desserts.
MK - don't really have a favorite...Cosmic Ray's is ok and so is Columbia Harbour House, but I don't really like either enough to call them a favorite. If it were up to me, I'd just have Dole Whips and cookie sandwiches from the bakery for lunch!