Have you heard of the PondScum DIY lights? Check them out.
http://forums.mtbr.com/showthread.php?t=245737
I have a set of the pond scums and they are pretty impressive. I didn't make my own (I'm not that handy), so I bought a used set from the "inventor".
It's a dual set up, one flood, one more of a spot.
Now being as they are halogens, the light is a bit yellowish, but not a big deal really. And I really only notice it against other riders lights (which are often bluish leds).
The battery is big (water bottle) and heavy, so if you worry about weight, then the pond scums aren't for you. But I'm heavy, my bike's heavy, so I figured what's a little more weight! LOL!
Now on the upside, they put off a LOT of light! It's almost light having car head lights when I switch them both on.
I'ts kinda cool to switch on my $80 lights and blow away everyones $350 lights.
If you're a littly handy, and want cheap, bright lights and aren't worried about weight, the pond scum lights are a great way to go.
(note* I paid $80 because they were used. To build a set from scratch plus battery and charger is still under $150 I believe).