I would also pick Artist's Point and California Grill. Actually did Artist's Point with a group of women at a conference on the recommendation of the concierge and it was really a nice dinner, very adult, great food, peaceful. We had drinks before dinner at the lounge next to the restaurant (Territory Lounge?).
How about Jiko? I love the lounge (ok, really, I'm not just hanging out at lounges at WDW, this is a coincidence!) at AKL...it's beautiful and very relaxing (even WITH kids!).
My runner up choice would be Hollywood Brown Derby. I really like that place, the food is great and it's a very stylish restaurant. And afterwards you can go to Fantasmic! If you're on the dining plan you can pay OOP for the Fantasmic! package and use the extra TS at another signature restaurant.