Well, last semester I kinda got out of control a bit (drinking 2-3 times a week) but I did not gain weight because I seriously punished myself physically after a hard night's drinking; and for the most part my diet was very solid. This semester I am shooting for one night a week (Fri or Sat).
I realize in college that completely cutting out drinking is nearly impossible and could definitely lead to some social awkwardness. I also say, after a weeks worth of hard work in the gym, on the track, and with my diet I can let loose one night and have fun.
Also, if you are gonna drink, stick to diet coke and hard liquor....no beer or real soda, that stuff will make you fat REAL QUICK.