Note the coin cell lights do not run 48 hours w/o dimming. They just dim slowly such that you don't notice them dimming.
Which isn't to say they are not handy little devices.
I really like the Infinity Ultra as Hacksaw notes, and load them with a lithium cell for better runtime, longer shelf life and better weight.
Headlamps rule.
Bottom line is LED + lithium batteries + multi level output is hard to beat.
And they just keep getting better and better... :-)
-john