If you are running the stock headlight (in the U.S.), an A3603 bulb is a direct replacement for the stock bulb-and much brighter. When you solder the posts together you have a 50 watt bulb. A pack of two costs less than $5. It does not melt the plastic headlight lens. This has been my favorite mod to my '01 650R I bought used in 2005 (I plated it).
I also installed the "LED tail light inner kit" from Wheeling Cycle Supply. I use the stock taillight for a brake light and this LED kit makes it much brighter.
I run the stock stator, and because of the LED tail light, the headlight no longer dims when I apply the rear brake.
These two mods cost less than $30 together, and drastically improve the stock lighting while keeping the stock stator.
