Dinner around Whitney
It's difficult to make appropriate suggestions without having specifics: cuisine preferences, whether you want something casual or a little fancier, and your per person budget for food only (beverages, tax & tip additional). That said....
Cafe Boulud is on 76th, just off Madison, one short block from the Whitney. Superb cuisine, excellent wine list, polished service, and lovely ambiance.
Cafe Boulud photos: http://www.flickr.com/photos/11863391@N03/sets/72157626251539228/
20 East 76th St., New York, NY 10021