i'm dorming with a friend who i've known since middle school. so i've known her for like 7 years already. but...like everyone has said, the lifestyles really do make a difference. It also depends on your own personalities and how much you're able to cope with. As of now, my friend has stopped talking to me and our other roommate completely. We've tried to talk to her countless time, but she just gets pissed off. the point of this was that people, in a way, do change once they go to college. everyone has their own set of priorities. no matter how close you were prior to college, thats not going to compare with actually living with them. It's like that say: "you don't know somebody until you live with them". It's true. You get to learn each other's quirks and stuff. If you're able to deal with each other and be able to speak out if something is troubling you...then go for it.
After a year with rooming with each other, there are only 2 end results: 1) either the friendship ends (or put on hold....?) or 2) the friendship gets stronger....
I hope that helps. Choosing roommates is really difficult because you have to find somebody who is really compatible with you. Best of luck with the roomie situation and in college!