My commuter is just whatever bike I happen to be commuting on, but I do indeed have 2 rain bikes. Fenders are the biggest difference from the rest of the fleet, one also has a chainguard and a coaster brake, the other has a triple and v-brakes with koolstop salmons... both are ideal for wet conditions, ironically though I tend to wet ride on my fixed gear with only one brake and narrow tires, it seems to give me better control than any other bike.