Not sure about best, but one of the brightest might be the Trustfire X100. From the reviews I've seen, the Trustfire X100 pulls around 4 A from 3 batteries, and should result in 1.5A at the LED assuming 25% driver losses. This should give 2000+ lumen out the front. A lot of assumptions were made here though, so it might be brighter or dimmer then 2000 lumen.. Calculations done with the T5 XM-L bin (511 lumen at 1.5 A) and assuming 33% loss from emitter to OTF. It is a big light though and uses 3-4 26650 batteries.
The checklist would be nice so we know what size and type of light you want.