Cinderella's Royal Table is inside the castle as noted by another poster. I think its really fun to eat there at least once. We took my parents there in 2005 and got a table by the window overlooking Fantasyland and it was fun. It was noisy but its Disney. Its very expensive and you have to prepay to eat there (at least you did the last time we did).
I'll also put a plug in for the Yachtsmen Steakhouse at the Beach Club. That resort is right near Epcot, you can walk there easily (its located just behind the World Showcase) and they have wonderful steak in a lovely atmosphere. Its typically a nice, quiet, unrushed meal. About the same price as CRT.
Also, at CRT you cannot drink alcohol, so if you want a glass of wine with your special meal, don't go anywhere in the Magic Kingdom because no alcohol is served in that park.
Coral Reef inside Epcot is also neat, its in an aquarium in the Living Seas Pavillion. Its going to have its fair share of kids but its very cool in there.
Tokyo Dining in Epcot is another one I like, very nice atmosphere (windows overlooking the lake of the World Showcase) and if you like Japanese food (they have sushi, tempura, teriyaki and lots of good things) its a great place to go.
There are so many wonderful places to eat in WDW, check out the menus on
www.allearsnet.com You can see prices and get a feel for places, they have every restaurant listed by location (resort or park). I love that site for planning.