I've had good experiences at Morehead Street Tavern. Mostly I was struck by how huge the place is. It looks pretty tiny from outside. But inside you'll find the main bar area, then a huge room with tons of tables and lounge space. My friend and I hung out on a couch there talking for hours one night, which is a testament to the chill atmosphere.
Morehead Street looks like a good place to have a party. I've seen quite a few groups having events in the basement. There is also a really pretty courtyard area that would be great for summer events.
A big plus is that it's right off the light rail.