Not so sure if I agree with the new/warranty is better/less trouble than vintage argument. If you're going to ride a bike any distance from home - you need to know some basic repair skills. If you're going to own a bike - new or old - your'e going to have to learn some basic maintenance skills. If you're at all handy with tools - that's not hard to do.
You can take someone more knowledgeable than you are to help you shop - for a new or used bike.
Say you can find a descent bike for under $400 (not hard to do, here's an '83 Schwinn LeTour for $345: http://sfbay.craigslist.org/eby/bik/2826249082.html), that's a lot of money left over to get it set up for your needs.