We used to eat obn Disney property all the time, but over the past couple years we've been dining off site more often. That being said, these are some of our faves:
Artist Point: This restaurant has been consistently good the past couple times we've been within the pasts year or so. My only complaint is that the menu is pretty stagnent. I wish they were a bit more seasonal and had some more "obscure" (for WDW standards) dishes. Overall, the execution is there, and the wine list is decent enough.
Flying Fish: This was our "go to" restaurant for many years, but they've hit a rough patch with us lately. I feel the menu has basically stayed the same no matter what season, and they execution of pretty basic techniques has falled short. We still love this restaurant, as it holds a special place in our hearts, and it hope they redeem themselves when we dine there in a couple days.
Beaches and Cream: Greasy good burgers in a great atmosphere. It's also one of the better deals on WDW property, especially if you have TIW.