The Cloak Room is a well known Capital bar frequented by those that work on the hill, cool spot for a late day drink. Check out the Continental Club on south Congress as well for a true Austin live music experience. The Domain has some nice stuff to offer, but probably not worth the trek that far north if you are staying in the DT/SoCo area. Rainey street is all around good for anyone mid-twenties and older, guaranteed good time anywhere on the street. Ah Sing Den is on the east side as well, swing style cocktails in a Asia meets french quarter atmosphere. Most of 6th street is infested with belligerent college kids, proceed at your own risk, west 6th has some to offer but still over run with college coeds and recent graduates.
If you want a diehard crowd and somewhat questionable atmosphere and location for a true jazz lounge, check out the the Skylark on Airport (far east side). The Whitehorse is awesome for a more late night country scene on the east side, but yes, hipster d-bags are slowly ruining it.
