Here is a photo of my son-in-law's electric bicycle that he uses for commuting from Fairfax in Marin County to downtown San Francisco (it takes about 90 minutes each way). The bike used to have a 3 kW front hub motor, with NiCad batteries hanging all over it, but it weighed a ton and he finely decided that there is such a thing a too much of everything - especially when the power runs out and you have to pedal.
So he rebuilt the bike with a 300 watt hub motor and Li batteries. I gave it a try this weekend and while it wouldn't pull me up much of a hill, it did well on level ground and I could pedal it up hill without having a heart attack.
