Vinoteca on 11th and U, great selection and awesome food. Also, Room 11 on 11th street in Columbia Heights. Great outdoor patio.
Cork on 14th (south of U). Some of the best food in the City.

Iron Bridge Wine Co in Howard County (close to MoCo though) is great.

I think Lepic closed, and I don't like Grapeseed:

http://www.washingtonpost.com/gog/best-bets/best-wine-bars,64321.html

For quiet and cozy, Ripple might be just the thing.

Sorry, MoCo's no fun for wine. (Has to do with the county bureaucracy and the horrendous alcohol tax.)
The only hope might be Grapeseed. Used to be OK; haven't been there in a long time.

Proof (Gallery Place); Vinoteca (U St.); Bardeo or Ripple (Cleveland Park), Cork (14th St.), Veritas (U St./Adams Morgan), Tallulah or ScrewTop (Arlington), Evening Star Cafe (Del Ray) ....

I don't know MoCo well, but I really like Vinoteca on U Street.

Proof?

Any recommendations for a great wine bar? Looking for some food, wine flights, and a cozy atmosphere to relax and have good conversation. Prefer recommendations in Montgomery County, but if you have a great recommendation somewhere else in the DC Metro area that'd be great, too. Thanks!