Personally, for a bike to do alot of more extensive and aggressive riding, I would stay away from older vintage road bikes. They look great, but weight and parts availability can become quite bothersome.

You can still find newish steel bikes. I'm riding a Spec Allez comp that is steel and its just a few years old. I think mercier makes a reasonable steel frame too. If nothing else, just get a no name frame for cheap off ebay and do your own build. Thats what INKDWHEELS did and he got a great bike and nice deal once all was paid for.