I have the Nexus four speed hub on my "rainy day/tropical storm/hurricane" bike. That's the bike I use when the weather turns bad, or I need to go through streets covered in a foot of water.

After both tropical storm Allison and hurricane Rita, my "storm" bike took me into areas that were closed to motor vehicles. Last year, I was visiting a friend whose low-lying neighborhood was so flooded that even the bridges out of the neighborhood were under water, and the Nexus hub was underwater for several blocks.

The combination of a Nexus hub, wide fenders, and coaster brakes enable the bike to work well when the water is up to the wheel hubs.

But, on a sunny day, with dry roads, I would rather be on a lighter bike with a few more gear choices. The Rohloff hub on a light frame would be my "ultimate" choice for an all-around urban utility bike, if the day came I had lot of extra money laying around. The Rohloff has enough gears to climb Mt. Everest, and is tough enough to last longer than I will.