I don't know how much you know about the Disney restaurant structure. There are table service (TS) and counter service (CS) locations. You may get ADRs (something similar to reservations) at TS locations. Many times ADRs are necessary to eat at TS locations. CS are first come first serve.
At MK our favorite TS is Crystal Palace. It is a buffet with seating at breakfast, lunch and dinner. There are Pooh characters that walk around the tables meeting guests. Our favorite CS tend to be Pecos Bills, Columbia Harbor House and Cosmic Rays. Just down the monorail from MK is Chef Mickey's (B and D) which young kids really like. Again a buffet with characters. Ohana is family style and on the monorail at the Poly. Band D are served there with characters at B.
DAK - Flame Tree Barbecue is a very good CS if you like barbecue. Tusker House has a buffet breakfast and dinner with breakfast having characters.
DHS - 50s Prime Time has home cooking with a 50s theme. The servers are your cousins, aunts, etc and ensure you have table manners and eat your veggies. The effect is often lost on young kids. Backlot Express and Pizza Planet are normal stops for us.
Epcot - has the widest range of restaurants. Biergarten (TS) and Sommerfest (CS) are the German and I like them. Biergarten has an oompah band at times with a dance floor. Kids tend to like to dance to the music and it is encouraged. The TS at the Mexico pavilion is pretty good with a good view of the park. The fish and chips at the England pavilion are pretty good inside or out.
There is a restaurant forum and I would guess the moderator will move the post. If so there will be a lot of input. Until then here is a link to menus by area to look at.
http://www.wdwinfo.com/wdwinfo/dining/disneydining.cfm