Boatwright's Dining Hall, Yak & Yeti, Le Cellier, Jiko, California Grill, Brown Derby, Be Our Guest and monsieur Paul. Thoughts?
Jiko, Le Cellier, California Grill, Brown Derby, and Monsieur Paul are considered "Signature" dining (two credits if you're on the plan). Le Celier and Brown Derby are open all day (lunch and dinner), whereas the other three are only open for dinner. I've not been to Boatwright's, Be Our Guest, or Monsieur Paul.
Jiko - when I went, this was one of the quieter places. The food and service were excellent and it really felt like an "adult" dining experience. We were in the wine room, which might have added to the feel. The appetizers were interesting and the entrees were very good. The One Last Cup dessert was really cute.
California Grill - I too am interested to see what the new menu looks like. Before the renovation, it was one of my favorite Signatures. It's much brighter (and noisier) than Jiko, but the food is excellent. (Plus it has a great view of the MK fireworks.)
Le Cellier - located inside Epcot, it's still an in-park restaurant. So this is a pretty casual "Signature" (meaning you'll see lots of families and folks in theme park attire). The food is very good. I love the cheddar cheese soup and Filet Mignon with mushroom risotto. The service is okay, but not quite are refined as at the other Sigs I've been to.
Brown Derby - located inside DHS, this is another in-park restaurant. The food is very good (Cobb Salad, Filet Mignon). The service is also good. I've done the Fantasmic! dining package and it's a good deal if you're going.
Yak & Yeti - The theme-ing for the restaurant is done really well. I like the entrees here (mandarin chicken salad, duck), but the appetizers and desserts weren't my thing (dim sum basket, fried wontons). My family likes to eat here because the food is good and it's a nice place to take a break from a busy day in AK.