That's a tough one. You can't just base a restaurant in Disney on food (at least I can't). Atmosphere is such a HUGE part of it. Here would be my 5:
1.Rainforest Cafe (either one, but I think I prefer the atmosphere at DTD more.)
2.Ohana (food and atmosphere here are both excellent)
3.50's Prime Time (definitely all about atmosphere)
4.Sci Fi Dine In Theatre (food's not worth the money, but a trip to MGM isn't complete for me without it.)
5.Marrakesh (only been here once, but the atmosphere is outstanding.)