For theme park restaurants, definitely BOG.
Outside the parks, it's a tie between Boathouse and Shula's. This is my opinion only, but I shake my head every time I see/hear people rave about both of these places. To me the Boathouse is an overcrowded, overpriced, nautical-themed version of the Cheesecake Factory, without the cheesecakes of course, but the food is on par (i.e. bland and unimaginative). As for Shula's, I find it obscenely overpriced and underwhelming. Definitely my least favorite of the upscale chain steakhouses, and I can't imagine stepping foot in there at WDW when there are so many unique dining experiences available.