I don't think those Cateye and similar LED lights are worth the money. I had the Cateye EL300 (5 LED opticube) and that thing had a goofy small spot about 6 inches in diameter and not scatter light that was not adequate for city riding not alone on pitch dark roads; I had a Zefal Halogen that was better then that light.

I think that LED's are rapidly improving and the Nighthawk might be the first "see the road" LED light to come out; but it's medium priced at only $75 and runs off of just 4AA batteries, and the battery pack won't take up a water bottle cage since the whole thing just sits on top of your handlebar. I have not seen this light in stores yet so I haven't been able to test it to see how good it really is. The LED's are great for long battery life as Raiyn discovered and the bulbs will virtually last forever.

I use a Cygo Metro that cost only $48 and has 2 beams: 1 6 watt flood and 1 6 watt spot for a combine total of 12 watts. The light will run for 5 hours on one beam or 2.5 hrs on both. It uses 6 D batteries instead of a strictly rechargeable system, though you obviously could buy rechargeable D bats. I found this light to more then bright enough for me; I ride in the city with just the flood only, and only use both beams when I'm on pitch dark country roads or bike paths; and I never have to worry about overriding the beam(s). The battery pack hangs off the frame not in a water bottle cage.