Thank you all. This has been extremely informative.
I had a Schwinn Super Sport 3 and it was stolen. I absolutely loved it. It was light, fit me well and was good for my needs. I want a flat bar because that's what I find to be most comfortable. I am not going to be doing any off roading. I travel to the college and the library, the rec center, makes it around 6 to 8 miles a day. I am going to look for some decent bikes on Craigslist and report back here to find out if the price being asked is fair.
Once again, thank you all for amazing feedback.