Don't overlook the Streamlight Scorpion. The tailcap has a positive click on/off, but no lock out. The Scorpion is as bright as the Surefire, and the Scorp. is only $35-40. I have found the Scorpion's lamp more robust than the 6P's.
Hi Natch,
As the owner of several Scorpions, I specifically would
not select this light as a life-depends-on-it kind of tool. While the rubber grip is nice, the bi-pin bulb can pop out of it's socket, leaving you in the dark unexpectedly. Worse, it stays stuck in the head which you can't open. I've spent more time than I like fishing bulbs out of the head with needlenose pliers.
The rubber can also get torn up pretty easy with rough use which allows water and dust to get in.
There were some reports from Afghanistan on CPF which indicated the Scorpion didn't hold up well over there.
The SF G2 is also only $35 and I consider it much more dependable.
-john