Originally Posted by mcjdeftones

Welcome, Epidoc! The amount of money you have to spend is really your only limit. I'd recommend going over to a LBS (local bike shop), not a Wal Mart or sporting goods store, and get fitted for a bike. There they can also help you consider if you want a hybrid or road bike. Generally, hybrids are cheaper and more economical if you are just going to be commuting. Once you get more experience riding, you'll get a feel for whether you want a fast, aggressive road bike or not.

Just curious, is your username derived from Epidemiology Doctorate? I happen to be pursuing a degree in Epidemiology, so of course that's what came to mind.