Lou the barber is by far the best barber around. Especially if you go to RPI, skip the campus barber who just messes your hair up and go to Lou's.
His place is covered in old sports memoriablia, and there is very rarely a wait.
Lou himself is an awesome guy who swears a whole lot but knows when its appropriate (i.e. he doesn't do it in front of kids, etc). He'll talk your ear off about stuff you want to talk about, not the normal dribble most barbers give you.
His haircuts take faster than any other barber I have been to and cost about $8-$10.
All in all, if you go to RPI, or live around RPI, Lou's is the place to go for a haircut.