i'm not a uwe student but this is what i have picked up from talking to my uwe friends and visiting the halls (so beware this is just my perception of what i;ve seen/heard):
*market gate - rave central. last year they had the police down pretty much every weekend trying to stop the partying. ok location, near train station and 10-15 min from broadmead, clubs & bars
*nelson house - also a mad house. much nearer clubs & bars. most people i met from here did arty degrees
*drake house - right next to nelson, very similar atmosphere
*transom - 5-10 mins from the centre, less partyish than nelson/drake/market gate
*frenchay - from all of what i've heard the people here are less up for a mad one. i guess a lot of the people who go here are into commerical/mainstream music and clubs like syndicate, oceana. if d&b, elelctro, house, dubstep, breakbeat, psytrance etc is more your style you;d be better off in nelson/drake/market gate. it's also quite far out from teh centre which causes travelling difficulties
i dont know anyhing about the other halls