I would suggest the Streamlight polystinger or stinger as Turbodog suggested as a first choice, then the UKE q-40 eLED.
Other lights that take the alkaline cells except the UKE Q-40 eLED would suffer from beam yellowing a few minues after being turned on, meaning that performance will be typical of store bought flashlights; yuk.
The pelican 1800 is not going to be bright enough, and trades people are usually carrying stuff so the two-handed twisties (you need both hands to twist the head to turn it on or off) would be hated right out of the package.
Stingers are regularly used by police officers, and other industrial users. They can come with a mobile charger (which can mount in the truck) and it can be ready to go all the time. (no batteries to fart around with)
Without going to fancy modified lights, this may well be one of the most readily available, simple to operate, economical to maintain lights out there for a tradesperson.
Go to
www.flashlightreviews.com and read up on the Stinger. You won't be disappointed. To the lay person (or non-flashaholic), it is like a maglite on steriods.