Cool places to hang out in London?

Okay I need someone who's been to Cape Town and will know the kind of places I'm looking for if I mention The Shack, Mercury, Assembly, Fiction, Rafikkis... I can't seem to find any places here in London that has that kind of vibe and people... Camden is really cool but where can you hang out apart from the markets that has the cool people but not too dirty? There's loads of cool places here but I think we looking for the cool people... Not jocks or heals and short skirts!! I'm not trying to offend anyone I'm just trying to get the idea across...Also the music we like to is rock n roll, alternative, bit of trance, drum n bass and electro.... That should help.. Your answers will be much appreciated!! Thanks a lot...