You should sit down and talk to your roommate. You said your personalities are nothing alike. If you take the time to actually talk to your roommate and get to know your roommate, you may find out you have something in common and actually end up getting along. I thought the same thing about my roommate my freshman year, but once I took the time to sit down and get to know her, I realized we did have things in common, and we ended up hanging out occasionally. We weren't best friends, but it made for a nicer living environment.
Also, if your roommate is doing things that bother you, you should them down and kindly suggest you create rules--how late guests are allowed to stay, what time each of you would like the place quiet so you can go to sleep, you get the idea.
If all else fails, you might want to talk to the person in charge of residents. You may have to just suck it up and be willing to move if you can't get things solved.
Post edited at 1:30 pm on Oct. 4, 2008 by RebelAngel08