Finally another person from Terrible Hole!
A Rose-Hulman student at that!
My wife and I currently live in TH, and I'm a 2000 Rose grad, Chemical Engineering.
Anyway, to answer your bike questions, you'll find mixed reviews on what is a good beginner bike and what isn't. For the most part we all tend to agree that starting small is best, but our views diverge where we define "small." Personally I think someone with your previous experience (dirt riding will not do much for you on the street though, other than teach you the very basics of riding), who has taken the MSF (or other training course, which I believe is offered at ISU), and who has the proper riding gear and attitude will do just great on a 600 as a beginner. I would advise against brand new for a few reasons though. Chances are you'll drop it once or twice while learning, so it's better to do it on a used bike than a new one. Also, let someone else take the depreciation hit on the new bike.
Personally I'm a Honda fan, but am looking at the Yamahas for a next one as well. Kawasakis and Suzukis just don't do it for me, though I would at least consider a Kaw. Go to a dealership (there is one here in TH, but they have very limited stock) and sit on everything you can to see what feels/looks the best to you. Washington St./US 40 in Indy has a number of dealers on it too, just inside 465 on the west side.
The God of the Old Testament is arguably the most unpleasant character in all of fiction: jealous and proud of it; a petty, unjust, unforgiving control-freak; a vindictive, bloodthirsty ethnic cleanser; a misogynistic, homophobic, racist, infanticidal, genocidal, filicidal, pestilential, megalomanical, sadomasochistic, capriciously malevolent bully. - Richard Dawkins, The God Delusion