if you want better answers trying being more specific.
LA and the surrounding area is HUGE there must be over a thousand different places (bars/clubs) to hit up, so where exactly in LA were you thinking???
also, what kind of music are you looking for?
dj or live music?
anyways here are my first thoughts:
Bang! (it only happens on saturday nights though – hollywood)
Medusa’s Lounge (echo park, i think)
Rage – and anywhere in West Hollywood (duh!)
There are these two place in china town that are a block or so away from each other. i think one is called mountain bar i don’t remember the other name.