I know this tread was for powering a bike for commuting/movement.

But Blast brings up the point of powering other items. I have long considered:
http://www.econvergence.net/electro.htm

I rode one for several hours at Superbowl XLII when they powered 30 minutes of the entire stadium with the stored energy.

It costs about $800 for a working set up, including the bike trainer (stand). Then you just put whatever bike you have in it and start pedaling.