Are you really set on the upright position? I would say you should at least take a couple of test rides on bikes with a little more bent-forward riding position. Like maybe a flat-bar "fitness" bike or a relaxed-geometry touring or cyclocross bike. The less-upright riding position of these bikes makes for greater efficiency, because you will be more aerodynamic and also because it is easier to put more power into your pedal stroke. Also, in some ways these types of bikes can be more comfortable for longer rides because your weight is more balanced (less weight on your bum, more on your arms).
Edit: Just perused the Trek site and the FX series (suggested above) is an example of what I was thinking of when I said a fitness bike. Many of the big manufacturers make something similar.
Last edited by Spld cyclist; 01-29-12 at 06:32 PM.