Have you done Le Cellier and the Cali Grill? You say without kids - are you wanting to "avoid" the rowdiness of family dining, or just looking for any nice suggestions? (I am not suggesting anything by that question, just to be clear- just wondering specifically what you would like in terms of suggestions)
If you do want a "quieter" meal, late dinner ressies are usually a better bet.
If you want totally adult atmosphere, there is always the V&A, but no DDP so you would have to pay OOP for that one and it is quite pricey, although apparently worth every penny.
Also, some of the deluxe resorts have good dining options. Epcot is probably the better of the theme parks when it comes to nicer restaurants, especially if you don't have kids with you and you say you have done most of those, so I am guessing you want to try something new. The other parks tend to go more the character/themed route.