Well Bansko is the largest resort but Pamporovo and Borovets will also offer you plenty of fun. I take it you are looking for cheap drinks and good night life? You can't go far wrong with any of them really.
Although the nightlife might not be what you want Momchilovtsi has its own new snowboard park and a cople of pistes etc. It is only 10km from Pamporovo and I can give you details of a large house which sleeps 14+ people.
Borovets is good but a few long fast drag lifts make it hard for boarding if your not very good. I'm goin bansko in feb and have looked in to it a lot, it looks like a much better resort. I'm 24 and have been borovets but cant wait to do bansko.
The night life wont be as good but who wants to be out clubbin till 5am when your snowboard the next morning??
Hope this helps
Paul.
Oh we're staying at the lion in bansko it look nice and is very cheap!
Boro, Boro, Boro. Cheap beer, lots of night life and once you get up the mountain a bit there aren't to many poma's to deal with. No park to speak off, but plenty of piste to keep you busy with. I went last year with a similar size and age of group and had a whale of a time. No issues at all. Do it
no1 else seems to b mentionin pamporov so i will!!! it has excellent nightlife specially in da english pub and the slopes are idel for beginners or intermediates....there are only a few slopes for advanced so it isn't ideal if ur tht dearing