I recommend a place called Yin Yankee on Fairmont to my friends. They started in Annapolis but opened a Bethesda location in the last year. It's a pretty innovative seafood place that does sushi and a lot of Asian-inspired fusion-type dishes. When I went they had excellent sushi, and I enjoyed the duck spring roll we got as an appetizer. Their website says it's under construction, but google revealed their menu page if you're interested.
I really like a Spanish place on Wisconsin called Divino Lounge. A really nice interior with lots of art on the walls and a lovely seating area. They have the usual selection of tapas, but skip those for a meal (maybe appropriate for an appetizer) and go for the paella. I was there a couple weeks ago and got the lobster paella and it was amazing. The only disappointing part of the meal was the flan we got for dessert - very unattractive presentation and pedestrian taste. But the paella and our goat cheese salad (and the copious sangria) were all incredible.
Last recommendation off the top of my head is for a place on St. Elmo called Red Tomato Cafe. Kind of a smaller Italian place that has standard pasta dishes, but the standout are the wood-fired pizzas. You can't go wrong with any of them. They also have a full wine bar and very knowledgeable servers. Last time I was there the server recommended a shiraz that was so great I'm kicking myself for not thinking to write down the name. It's a great cozy date restaurant.
