I use one of these:

http://www.cygolite.com/2-Products/5-Nitro200.htm

NiMH battery completes charge in ~3 hrs maybe. Full lighting lasts ~2.5 hrs I think (5 legs of my 30 min commute; I was leaving my charger at work and fully charging it every day, but eventually wound up getting another charger for home 'cause it was getting more use over the weekends).

Use a cateye ld1000 (the bright one w/ 10 bulbs/LEDs/whatever) for the rear. Switched to disposable Li batteries, but that was right when the days started getting longer, so they've been idling in the light all summer.

Anyway, those lights, even plus an extra charger (and I also have an extra mount to switch the cygolite between bikes) all < your budget.

w/ the cygolite I get comparable visibility up ahead, more or less corrected for my speed, as w/ a car and car headlights (less absolute vis, but then I'm going slower), and people can definitely see me. I wonder about HID occasionally, but also wonder if that would be TOO loud. On the one hand, I'd rather blind/confuse cars than have them think they can catch/pass me when I don't think they can, conversely I wouldn't want to potentially blind bikers coming toward me on the trail.