Well, these days I'm really into that 4Sevens Quark I have, mainly because it has such a low dim mode. The Quark doesn't come in an 18650 option directly, but there is a separate 18650 body tube available, which will work well with either the 1xCR123, 1xAA, or 2xAA models (just not the 2x123 model, really).
4Sevens just announced in the last few hours that the Quarks are now to ship with the new R5 emitter, and are clearing out the 'older' R2 models at a 15% discount. I wonder if the UER 10% discount will work on top of that?
Of course, there's still the dealextreme option if you're on a budget, but I have to say I'm well and truly tired of cheap lights that just stop working!
What sort of budget were you on again?