much like knives, there's no such thing as "best" - but I'm a fan of the surefire protac and fenix PD/LD series single AA and AAA lights.
Even maglite has reportedly done a good job of getting into the LED game, though I haven't tried one of theirs yet. (keep looking at the mini-mag)
as a budget light, Wally sells a nice 3-color (white, red - for night vision, blue - for game tracking) Bushnell branded light that I carry on my hunting bag and have one next to the bed.
indoors I try to limit my lights to less than 100 lumens -- it gives me better run time and reflection off walls doesn't impair MY vision.