O'hana's and Le Cellier in a toss-up. However, Boma is right up there with them.
Honorable mention to Chef Mickey's - while the food is decent if unspectacular, the fun atmosphere makes it a great destination to get into the Disney spirit.
Well, it wouldn't be a trip to Disney w/out lunch at Crystal Palace. It is so pretty, and offers a great respite. Not to mention we love the salmon and the kids find so much they love to eat too...and then the chars...it's just win win all around for our family.
That being said, my favorite restaurant is probably in Mexico. We had the romantic dinner (w/ the kids who were entranced by the boats, volcano and just quiet nature inside). But I haven't gone back....don't dare hope we could duplicate that night...and so want to hold the memory strong in my heart.