Originally Posted by mtalinm

Sure, you can do a 20m commute. I took up a 15m-each-way commute last November, and you are in much better shape than I am. Especially if it is in Santa Monica, where you don't have to deal with weather. how are the hills? the one thing you might find at first is that the hills are really tough (I avoid them whenever possible).

if there are a lot of intersections on your route and you will be stopping and starting, then I would highly recommend an internally geared hub, like the Swobo you listed. If there are any hills though you might want an 8-gear hub like the Shimano Nexus, Shimano Alfine, or Sturmey-Archer 8.

If the weather is good then you're probably fine with rim brakes and a chain.