Originally Posted by Bacciagalupe
Either Downtube or Brompton.
Did you mean Downtube or Dahon?
OP: How tall are you? If you're under 6', try the Dahon Curve or Downtube Mini. They're both 16" wheels, internal gearing and under $400 new. Both are excellent bikes. Here's thread that compares the two:
http://www.bikeforums.net/showthread...+downtube+mini
You can go cheaper by buying used...