If you're looking for something more chill than Berghain, which is as close to Dante's vision of hell as it gets (in an awesome way), Madame Claude’s Sunday open-mic night is the best place to see live music. In a former brothel. With chairs on the ceiling (sometimes it's best not to ask).
P.S: The Labrynth (http://exittothelabyrinth.com/) art project at Wilde Renate club could only happen in Berlin. GO.