The outdoor concerts at this former squat are great. They also show movies during the summer.

Personally I don't care much for the bar part with all the live soccer transmissions, but some of the best indie concerts in Vienna have taken place here -- it's always worth checking their website to see who's playing. Beware, however, that it's often WAY overcrowded. (Examples of artists too popular for the Chelsea: Xiu Xiu, 13&God).

The Luftbad is a cozy, intimate, down-to-earth bar tucked away in a small street near the Apollo cinema. It has a little stage, which often hosts local funk/soul/acoustic/world music/jam/hip-hop bands.
I haven't spent a lot of time there, but I've always gotten the impression that everyone else in the room knows eachother personally. Although that's probably because we actually crashed a private birthday party the first time we wandered in. I gotta say, the cake was delicious.

This location is now closed. The same crew now organizes events at the Szene Wien and the Gasometer.

Intimate, not too attractive little venue. Live shows are mostly punk, ska and similar styles, but they also host a bunch of indie clubs.

One of the nicest larger places to see a live indie music show in Vienna. The backyard garden is great in summer.