I'm a big fan of LED lights myself and I have several, but I'm an even bigger fan of lights that take standard batteries, AA, AAA, C, D etc. A lot of LED lights take special batteries so I shy away from them. Ideally I like all my battery operated gear to take the same battery size.

I'm beginning to see some nice AAA powered LED lights coming on the market but i haven't seen one that fits nicely into the side pocket of a leatherman sheath.