The California Grill - On top of the Contemporary Resort, this restaurant overlooks Magic Kingdom and if you book for the right time you can watch a the MK firework show (music piped into the sound system)!
Cinderella's Royal Table - Inside the Magic Kingdom castle, this restaurant must be pre-paid but includes a picture of your family and Cinderella herself (printed out and handed to you during your meal). Although the food is not GREAT, the atmosphere can't be beat.
Victoria & Alberts - at the Grand Floridian, this is a pricey but very elegant dinner experience (also very romantic). Great for honeymoons, anniversaries, and the like.
1900 Park Fare - at the Grand Floridian, this is a charming character dining experience (buffet) with Alice in Wonderland and Mary Poppins
Brown Derby - in Hollywood Studios, this restaurant is pricey but themed perfectly to match the original in California (lots of signed drawings of celebrities). One of the best meals at the World. To make this a real experience, pair it with VIP seating at Fantasmic - this must be purchased in advance, but is well worth it!
Sci-Fi Dine In - in Hollywood Studios, this restaurant is not very good (at least our meal wasn't), but it has a fun setting that will be adored by children (one of the few restaurants I remember visiting as a child). You sit in a car with built in tables and watch movie shorts while you eat!
Garden Grill - in Epcot (The Land), this revolving restaurant features family style meals that you can enjoy while watching the enchanting scenery go by.
San Angel In - Located in the Mexico pavillion in Epcot, this is truly the coolest themed restaurant in Epcot. You can even enjoy a boat ride that passes through the restaurant!