First, my picks:
Cinderella's Royal Table is the best for atmosphere (you're eating in the Castle!) or for young girls if you do a princess meal (breakfast or lunch) Second is California Grill- you can see the castle, and fireworks if you time it.
Kona and 'Ohana are best for food quality and overall enjoyment of the meal. It's just my taste 100 %.
Best for kids is probably Chef Mickey's in the Contemporary.
Best snacks are: Fiesta Margaritas in Epcot (Mexico) and Ice Cream Sandwiches from Main Street in MK.
You can also use the search tab at the top of the page to search old threads if you want more info- there have been threads about "best counter service", "best snacks", "best at xxxx locale" etc. Those might be helpful, especially once you decide where you're going to be. (Itinerary) Really, most of the best places are in resorts, not the parks, so there might be 6 great dinner places in resorts that appeal to you, but itinerary wise that might not be reasonable. You'll have to find places that match your schedule.
You might also want to look at the affectionately termed "food porn" thread aka "Post your Disney Dining Pictures Here" to see what's offered where and get a feel for what you'd prefer. Also , look at the menus on allearsnet.com. Menus can change, but signature items will usually remain and the type of food and pricing will rarely change unexpectedly.
Decide how many table service you can afford/care to eat at/have room in your schedule/belly for and where you will be before you can really pick the best places.
Once you've narrowed it down, it's easier to compare. Disney has like 300 restaurants! Hard to say which ones are the best exactly - some have great food, great atmosphere, great value, food for kids, etc.
Good luck!
