If you're going to get a 3-series, I'd probably not get an '01. The main reason for that is the terrible steering feel. This you might already know, but if you haven't driven one, give it a try... very dull. The other issues aren't really worth worrying about.
That said, I have a friend with an '01 330i w/the sport package, and he seems to like it enough. It has had the common cooling system issues and other various gremlins pop up, but I think overall, it's been acceptable in the reliability department. But getting back to the fun-to-drive part, it's just not. There are better (and more reliable) options for the money. They can look cool, though.
As far as the Boxster is concerned, I'd probably not want one for an only car in college. I'd worry about it too much, it has the potential to be expensive, isn't all that practical... but it would be a hell of a lot of fun. Honestly, if you're stuck on a roadster, I'd probably get an S2000 or Miata over a Boxster while in college. They're just as fun, but a bit more, oh, Japanese.
