You are likely going to be in the 52 to 54 cm range frame size, or 21 inch frame. You really need to dial in on your sizing first. Then use some generic criteria to judge bikes: alloy crankset, cromoly frame (name brand even better), alloy rims, downtube shifters, alloy seat post, alloy handlebars, room for fenders.

I would consider any bike in good condition that meets that criteria to be a "good" bike. Just set a budget, know your size, and start looking for a deal. Around here, such a bike in ready to ride condition would cost $175 to $200. Deals can be had for less, but the deals usually require some repair/rebuild work. If you do the repairs yourself, great. If you have to pay a dealer to do them, then the "deal" becomes a lousy deal. Having a shop do a basic rehab of a vintage bike can cost $250 or more.

My next stop if I was you would be to one of the local co-ops. You can probably see a lot of options, sizes, and get some leads on good bikes.