My two favorite places in DHS are the 50's Prime Time Cafe and Mama Melrose's. We usually go to 50's, not so much for the food, but for the fun. If you get a good server, it can be one of the most memorable parts of your vacation. Mama Melrose has some very good Italian food, and it's not as crowded as the 50's (at least, it hasn't been when we were there).
DHS also has the Brown Derby restaurant, but the food is a bit too fancy for DH and I (and expensive!).