It really depends on what you are looking for, and each place has definite pros and cons.
Liberty Tree Tavern - nice atmosphere and good classic food. It can be a bit cramped, though, and it is VERY busy and noisy.
Crystal Palace - BEAUTIFUL place with a very nice selection of food. Again, noisy due to the characters, but the space is large so it is not as overbearing
Tony's Town Square - Really fun place. The Italian is very good for a theme park, and you can expect what to find here. If you are picky about your Italian, though, this might not be the absolute best. However, I tend to be somewhat picky, and I like it.
Spoodles - I tend to agree that Spoodles is good, but it has started to pass its prime. However, I have heard the food is fickle here, so it may have improved (haven't been there in a couple years).
1900 Park Fare - This is a very nice little buffet. It looks like a child's nursery to me (well, a LARGE nursery). The buffet is good, but it is a little bit limited. However, the food is traditional, so picky eaters will find familiar things. If you have WTP character lovers, this is a great option.
Overall, I would suggest Crystal Palace first then Tony's out of this list. I think they have the best overall atmosphere.