Lunch in the theme parks...
At AK we always eat at Tusker house, that rotissiere chicken/mashed potato combo is wonderful.
At MK if we want sitdown we eat at Liberty Tree Tavern. Wonderful lunch menu. Another option would be to hop the monorail quick over to Kona Cafe at the Poly for lunch. It is absolutely fantastic.
At EPCOT...we can eat almost anywhere for lunch. Our favorites..which we rotate through..lol. Biergarten, San Angel Inn, Chefs de France and Alfredo's.
At MGM our favorite used to be Hollywood and Vine, but we haven't had lunch in MGM in years. When you are in MGM it would also be very easy to hop over to the Dolphin and have lunch at Fresh. We have only had breakfast there, it is wonderful and people that we have talked with that have had lunch say it is wonderful as well.
good luck and happy eating!