There are so many restaurants at Disney that would be great for a romantic type meal, but here are a few that I think might be worth investigating further.
Bistro De Paris - EPCOT
I haven't been here yet, but have heard somany great things about it I hope to try it soon! Has a fixed price menu with wine pairings or you can buy a la carte. It is also not on the
DDP, so you are less likely to find a crowded venue, and there should be a more adult and discreet clientelle.
California Grill - Contemporary Resort
You just cant beat watching the fireworks while at the California Grill. The food is great and view of the Magic Kingdom stellar. No guarantees that you will get a good view although you can always go to the viewing area to watch.
Citricos - Grand Floridian Resort
One of my personal favourites, it has a great upscale feel to it and fantastic menu.
Artist Point - Wilderness Lodge
One of the quieter signature restaurants, with great food and a lovely setting, especially if you get a seat at the window overlooking the grounds!
Thats about all to recommend from me. Hope this helps!