I was running a pair of cheap 55w lights on my Nighthawk for a while to try them out; $25 at some auto parts store. They killed my battery and fell apart from vibration (mounted to the fork legs....)
I replaced them with a pair of these, and LOVE them. Each one is brighter than the stock headlight, but they are flood beams, so at night, the stock high beam does shine further down the road.
I do a lot of riding down back country roads at night, so I really needed to see and be seen. Probably over-kill for what you need, but that's better than going cheap...
http://stores.intuitwebsites.com/hstrial-QualiRegResou/-strse-41/Model-60-LED...This link now shows them as $100 each, I don't remember paying that much, but I bought mine well over a year ago.
Also, I got a wiring loom for them from EASTERN BEAVER. Great guy to work with....
http://www.easternbeaver.com/Again, maybe overkill for your purposes, but it all worked great for me....