I have to disagree with this love fest for internal geared hubs. They are heavier, less efficient, have less gear range, and the rear wheel is much harder to remove and replace when changing flats. In my experience derailleurs don't require much maintenance at all. If you want a simpler bike for commuting in a flat area get a fixed gear or single-speed bike. I ride fixed gear in San Francisco, all you have to do is get out of the saddle and stomp on the shorter hills and do your best to avoid the mega steep ones.