You don't say what your proce range is and whether chains are OK, but based on your location alone, I'd recommend the Sweetwater Tavern-Merrifield. It's right at the Beltway and 50. It's a Great American Restaurant and that chain has impeccable service. The food is very good too - and the free bread/butter is to die for.
http://www.greatamericanrestaurants.com/sweetmainmeri/
Coastal Flats is another GAR, but the one close to you (in Tysons) isn't as nice as the one in Fairfax, I think, and that might be a bit too far for you.
GARs don't take reservations but you can call ahead and get your name on a list. Weekday nights should be better than weekend nights.