Just an FYI...i gave my first dynamo a try. I have to say i am very impressed. It's much brighter than i expected, and it only cost me less than $20. It does add quite a bit of resistance when engaged, but not something noticeable when I ride. If i like using this unit, i will eventually upgrade to a hub based dynamo and a better light.

Thanks everyone for pointing me out to the right direction. I am hooked to Peter Whites site. There is so much to chose from, and I'm loving it

Some pics of my power bottle