I'm in a similar situation. For the last year and a half my roommates have been awesome. Quiet, neat, and all in bed by midnight. I'm an extremely light sleeper, but sleeping was never a problem. Three months ago one of my roommates bought a house and moved out. I placed an ad and found a new guy. I thought he would be fine, and explicitly told him the first day he moved in that our house is generally quiet, and by 11pm I didn't want to hear a peep.
Of course the first week he moved in it was Frosh Week and as a result he was out drinking all week, coming home late, and making too much noise. I decided to let it slide as it was Frosh Week. After that, once I was in bed and he was making too much noise I would tell him to STFU.
Then, Thursday night, he came home at 2:30am, crashing and banging around. I woke up, went downstairs, told him to STFU, and went to bed. He continued to keep me up until 6am, despite my repeatedly banging on the wall that separates our rooms. I start work at 7am. I had been up since 2:30am, and got a little less than three hours sleep.
When I came home yesterday I ripped into him good. I took him down a few pegs and hopefully the days of his waking me up are past.