Green Dragon
Belmont Station (always has some interesting stuff on tap)
Concordia Ale House
Bottles (not a ton of taps but usually good stuff - pinball & shuffleboard in the back :rockin
Apex sounds good but haven't had a chance to check it out yet...
oh, and I agree about Hair of the Dog - can't miss it.
Went to Apex recently and it's really awesome. Be warned though, it is cash only.
Horse Brass is great, as is Concordia Ale House and Green Dragon
Henry's on 12th has a lot of beers as well and is worth checking out.
If you like sour beers at all, you have to try Cascade Barrel House (it's right by the Green Dragon).