My friend has some LED flood lights on his 4x4. They throw a ton of light out and use hardly any energy. They throw more light and use less energy than the halogens he had. For a headlight, you need something designed as such, so the DOT certification is important. Otherwise it's probably more of a flood type beam and will blind people coming at you. That said, I think an LED headlight would look out of place on an RE but that's just my taste.
Not all REs have a decent charging system. My 2010 C5 can't even run a 55/60W headlight without killing a battery. Everything else in the system is stock. I'm still trying to figure out why. The alternator is throwing out plenty of juice so it's probably either lame wiring or a marginal reg/rectifier. Regardless, I run a 35W headlight in the meantime so I don't kill batteries and end up stranded on a regular basis.
Scott