I voted for Le Cellier with a very close second being Chefs de France. I love them both. The only one I would NEVER vote for is Rose and Crown (tried it 3 times, disappointing all 3). We did like Alfredo's, but didn't love it. Biergarten is just ok (it would probably get my fourth place, I used to like it until last time we were there they were adamant about sitting us with other people even when there were tons of empty tables all over the restaurant so our family of four was smashed up against two other couples who didn't know each other and everyone just talked quietly and we kept having to move for them to go to the buffet, anyways....way off topic).
We're trying San Angel Inn for lunch which I'm sure I'll love (I like typical Americanized Mexican food which is I've heard comments that their food is like), even though I know others in our party who won't care for it (not big mexican food fans).
I wish the American pavilion would have a TS restaurant that had things like Philly cheese steaks, Chicago deep dish pizza, Georgia peach cobbler, Apple Pie, California pizza, etc. just different things our great country has to offer (yes, I know you can get these at a lot of restaurants around Disney but you can also get Italian almost everywhere). Not a big deal anyways as I love a lot of the food already at World Showcase.