My commuter bike is an old style road bike, fairly high-end in its day, and still as good but at a fraction of the price.
Its hard to recomend a particular bike when you are looking for something used. If SS is your thing, then get something with horizontal dropouts. These are also good for hub gears.

Steel can live out-doors in all weather if you apply framesaver/wd40 to the inside and car wax to the outside. Pack all the bearings with lots of grease and use a well-sealed bottom bracket .
Definately fit a rack and fenders. This is not only useful but will deter many thieves. Racks are good for absorbing scratches when you lean the bike.