Regarding frame material. You could do a search and read until you are blue in the face and then still read for another 1000 days.....

Personally, I would not be buying steel as my 1st road bike in 2007. I would be looking for aluminum with carbon fork and seat post or maybe even seat stays. With your budget you should be able to get something easily. Here are some to consider:

None of these are a brand endorsement, but rather just to show you some options in the new market in your price range.

I understand about craigslist. The good deals don't last long and it can be difficult to get hooked up for a test ride and you need to know the right size for each brand as it can vary.

http://chainwheeldrive.com/itemdetai...ogId=39&id=888

http://chainwheeldrive.com/itemdetai...ogId=39&id=930

http://www.bikesdirect.com/products/...tal_ice_08.htm

http://www.bikesdirect.com/products/..._08_carbon.htm

http://www.feltracing.com/08/product...,1515&pid=8665

http://www.feltracing.com/08/product...,1515&pid=8667