Ok here is one reason that some of you may not be aware of and I certainly wasn't until the other day, and most of you probably would never have to worry about this but:

The only likely reason I will ever shave my legs for cycling is:

My leg hair is so long that while I'm riding my bike little bugs get trapped in my leg hair. If I ride through a swarm of flys/mosquitoes/whatever then my legs will literally capture half the swarm and carry them with me for miles and it is quite possibly one of the most disgusting gross things I have ever experienced, to have 30 or 40 bugs covering my legs.