I'm sorry I didn't see this thread before....
guessing that now is too late, but anyway - in ljubljana you have Fun Factory, but i'm not sure if it is working at the moment... the same thing is with Media Park (in 1 month SOS is coming, Zabiela also in 2 months)... Club K4 is cool dark place, usually mnml & tech house, some breakbeat and/or electro... soon their guest will be Ellen Alien...
there's also Global, which is actually mtv music, like any genre and stuff....
but definetly the best club in hundreds of kilometers is Ambasada Gavioli... one of the most beautyfull clubs I have ever seen... just, it is not really in ljubljana, 40 mins of driving from there.... almost all the biggest house and techno names were there...
check ravespace.net for more info about gigs in slovenia