Aww, if you’re from Seattle, why don’t you stick around and go to good 'ol SPU? I moved here to go there. 
But seriously – the thing that surprised me when I was a freshman (and this was only 7 years ago) is that even at a conservative Christian university, there are still plenty of people around who drink, smoke, do drugs, etc. And it’s possible that your roommate/hallmate/etc. may be one of them. I’m not trying to scare you, but be prepared and try not to judge – there are so many facets to Christianity and Christians!
Also, bring a can opener. That’s one of those things everyone forgets, and when you want to have some Campbell’s soup because the dorm food is gross, you’ll really want a can opener (a few dishes are good, too, and a hotpot). You’ll be popular during cold season, too.
And since you’re from Seattle, if you drink coffee, be prepared for weak coffee everywhere else. Even Starbucks changes their “standard” blends for different regions.
Leave your door open, and say “hi” to everyone who walks by. People will stop to make friends. Especially if you have something fun or quirky posted on/near your door, or a quote board, or food.
Don’t be afraid of the opposite sex. I’ve always been a tomboy, so I made friends on my brother floor quickly. I was amazed when, halfway through the year, 5 girls from my floor wanted me to take them to the brother floor, because they were scared to go by themselves. There were 5 of them, fer cryin’ out loud! So I took them up to introduce them to some of the guys (who were all very nice and not at all threatening), and when I got caught up in conversation, they left because they were to scared to make friends on their own. I thought that was pretty silly.
Keep your room decent! It’s more inviting if there’s a place to sit when friends come in.
And I agree with DeVena – get to know your profs. It’s well worth your while to get to know some adults who aren’t your parents or your parents’ friends, and get the benefit of their life experiences.
Have fun! And if you can afford it, don’t try to finish early. You only get the college experience once, I figure, so cherish it while you can. Let us know how it goes!