We never argue with The Teen over friends, music, books, clothes, food, what he buys with his own money or computer time.
He recently has been given unlimited X-Box time, but he loses it completely if his grades aren't kept up. He never watches TV so that doesn't matter. He doesn't get to see 'R' rated movies that have a lot of sex or violence in them (and he really doesn't want to either) but the lesser of the 'R' ratings I have allowed him to watch.
Overall he makes really good choices about what he puts in his life so we feel comfortable with what he does. We're working towards letting go completely because in 1-1/2 years when he turns 18, we won't GET to say anything to him.