As I type this, a Surefire E2D LED Defender rided in my left jeans pocket, and as the AmEx slogan goes, I don't leave home without it!
Personally, the Surefire is the only game in town! JMHO! I have several and think they're the best in the business. I just recently upgraded from the L4 Lumamax to the E2D LED Defender. Only 20 lumens difference, but the lens set-up is so much more to my liking!
The L4 is a great light, but is best suited to relatively close quarters for best effect. If you try and see something more than 25 yds out, it just doesn't have the 'throw'. In the deep woods where there are lots of brush and trees, its great, just like inside your house or any other building. The L4's output is 100 lumens.
The E2D LED Defender is just as Fuzzdaddy descibed except that it uses an LED with a special TIR or 'total internal reflection' lens, which throws a much tighter longer beam. This lens is what I have been looking for, living out in a rural setting. It more than doubles the effective range of the the light. It also throws a fairly good periphial beam. The output of the E2D LED Defender, is 120 lumens.
Both lights have their place, and are absolutely, reliable. You won't be disappointed!
Hope this helps!
J.