My husband and I have teenagers so we are able to enjoy one or two dinners by ourselves. We really like the California Grill at the contemporary resort. It has faboulous food and sushi. The bar is a great place to hang out and if you are there later you can see the fireworks. You will need to make advance reservations through the wdw main reservations number. This year we are trying the emeril restaurant at City Walk. Sounds great but can't personally speak to the quality of food.
Yachtmans' Steakhouse...we love to go there for a "date night" or with the crew...3 boys (8,5 and 2)...either way the food and service are always awesome!
I'll give a second vote for Melting Pot! Definitely a unique experience and a romantic environment. We have one locally...seems like it's about $30/person.
DH and I love a good steakhouse, so we are going to Shula's Steakhouse in the Dolphin for our anniversary dinner while we're there. The bonus with that is that you can drop off the kids at Camp Dolphin in the hotel. The kids will be fed dinner there, and you get 2 hours of complimentary time at Camp Dolphin when you present your Shula's receipt at pickup.
Columbia's in Celebration has a nice atmosphere. We were there with our then 2 yo and I felt a little out of place. It was definitely more of a date restaurant - and the food was very different and yummy. Plus you could stroll around Celebration afterward, which is much quieter than DTD.