Marvin is my go-to spot. I always seem to end up there, even though a lot of people don't enjoy it as much as I do.

Avoid weekends from 11pm-1am. Way too packed and nightmarishly long lines.

Other good spots by the same management/ownership are Local 16 (a little younger crowd and also gets way too packed on the weekends) and 18th St. Lounge (a little older, not as packed, but charges a cover on weekends--live music included).