Welcome,I like the Dahon Speed Uno, it is a single speed but with the track dropouts could be upgraded to a internally geared hub, ie 3,5,7 or 8 speed in the future if needed. http://www.thorusa.com/dahon/current/speeduno.htm The Raleigh 20 is a favorite here also for modernizing or riding as is. Check Craigslist or Ebay for those since they havent been built for quite a while.