I guess the question you should really be asking yourself is this - What do you want to do in college? Are you there for the social experience or to learn? I am seriously not being snarky here, because I think college is great for both of these things and both can teach you a lot about the world. But I think this is one of those situations where one can't have all of his cake and eat it, too. You do have to recognize that, on some level, you will have to choose between these things at times. People who wrote above about scheduling classes for partying/long weekends (something I did in the last semester of my senior year only) probably missed out on some good classes. But that's cool. It's a useful choice to make. They probably knew how to behave when interacting with people their own age by the time they got out.
I, on the other hand, I went to one of the biggest party schools in the country and I didn't get drunk for the first time until I was 21 1/2. Much to my intense regret, I had the same, boring, Ayn Rand reading, jackass boyfriend the entire four years (I didn't meet DaveB until three months after I graduated). I didn't go out on Thursday nights, and took classes every day of the week, whenever they were offered. Monday night? Sure! A two-hour honors seminar first thing in the morning? Hell, yeah! I graduated with 20 more credits than I needed, Phi Beta Kappa, with honors, near the top of my class.
When I got out, I was a total fucking social retard. It was worth it, though. I would do it the exact same way, all over again, with perhaps the exception of the jackass boyfriend (I'm going to concur with everyone who tells you to approach serious relationships with caution, but don't make that your lame speech to girls/boys who express interest). I spent 22 and 23 learning how to act like a normal human being and learning how to drink. I'm still not very good at the drinking bit, though I am capable of bar conversation now.
What kind of lame, broke-ass school makes someone buy their own scantrons? That's just sad.
If you're going to stay in the dorms, get your own room as fast as you can. I had one for my last three years and cannot tell you how nice that was. Dorms are breeding grounds for communicable disease and psychosis. Having a lock to which only you have the key is vital.
Yes, yes. Fear the used CD store. I have a very vivid memory of walking down the street, brand "new" copy of Out of Time (oh, yeah - listen to REM in college, my friend) in hand, thinking, "I have 250 dollars in my bank account. This cost me 8. There are 10 more weeks in the semester. So I can buy one of these every week..." Bloodsucking bastards.