I used one of these for my front headlight:
1 WATT WHITE ULTRA-ULTRA BRIGHT LED | AllElectronics.com
and one of these for the rear light:
CHROME 4 LED DISPLAY, RED | AllElectronics.com
If you want to get real fancy you can put a rectifier in and convert the AC current coming from the white wire to DC current. I intended to do this to eliminate the flickering, however the engine rpms are so high the flicker is so fast you cant even tell its flickering unless you are idling.