| Definitely get a bike. You might find gears helpful, but I don't see them as a must. If you're curious, there is one route which people usually avoid due to its steepness (perimeter rd. from campus market -> redbrick dorms). Even so, road / mtn / cruiser are fine and seem to be equally popular.
I would advise against getting something expensive though, esp. if you live in the dorms. Unless you plan to keep it inside, your bike will take a beating from the weather and other careless folks using the racks. You also risk getting parts stolen, which is unfortunately very commonplace. I hear the thievery situation is even worse in the off campus apartments.
If you do insist on getting something nicer I'd recommend going for something used on craigslist. I wouldn't wait to buy one @ SLO, though; being a college town, SLO's listing hardly ever has any cheap deals | 
College Confidential is dedicated to providing the best free college admissions information available on the Web, through our many articles and this discussion forum.
