I think the California Grill at the Contemporary during the evening during Wishes is also very romantic - in fact I saw a male couple holding hands and enjoying the ambiance on my last trip there. It definitely sets the mood.
Most romantic and elegant of all, if you guys want to get really dressed up and don't mind spending a few (hundred bucks) is Victoria and Albert's at the Grand Floridian - they even have a person playing a harp there and it's very intimate - you can ask for the Queen Victoria Room - only 4 table settings in there and there's even a chance you could have the room to yourself - I did once.
Basically, any of the signature restaurants at the resorts will offer you a lovely romantic dinner evening. In general, for a more quiet dinner, stick to a resort restaurant (but not a buffet). The theme park restaurants are usually more boisterous and noisy. Not that that stops one from having a perfectly great time, but if it's romance you want, the resorts' dining experience is superior.
For a more casual and fun meal that can be kind of silly romantic, you could try the Sci-Fi Dine-in at Hollywood Studios as the theme is a drive-in movie theater and you get to sit in a car in like a simulated outdoor arena with a movie screen in front of you where you watch old B-movie horror clips like Plan 9 From Outer Space. However, you will probably have to share a car, as they have multiple rows, so that's something to consider as well, if you're looking for more privacy during the meal.