Originally Posted by
exile
I think your current bike would be fine for a 6 mile commute. If you really want something better I would check bike shops that sell used, coops, pawn shops, yard sales, and craigslist. You can also check and see what campus security does with confiscated bikes as well. I do like the early to mid 90's rigid mountain bikes as good all arounders.
Security may or may not be a concern as every college campus is different. Check with your campus police department. Just make sure your bike is locked properly. I see a lot of bikes locked on our main campus with nothing more than a cable lock. But since our campus is located in a suburban and relatively secluded location I don't hear of anything ever being stolen. But it is better to be safe than sorry.
+1 Your bike is probably good enough for that commute. Its easily replaceable if it does get stolen and having that type of commuter bike makes it much more relaxing for me personally to commute. No panic feelings if I leave it there for hours. With the money you save you can buy something nice to ride for fun and/or with your friends. If you have ridden your current bike that long you are used to its quirks already. Get a rack and something to put stuff on it and replace anything that goes wrong on it with cheap stuff from a bike coop. If you want to upgrade your commuter at some point snag a 90's trek 800 series mountain bike or something similar for less than $100 (you might find one in a dumpter) and you will be good to go. Also after a few weeks or months of riding your current bike you can assess the security of your campus and see whether you want to ride something nicer.
Single-speeds can be fun bikes I just got one and I love it. Just don't overpay if you decide you like that type of riding.