I'll have to disagree with some of the other people here on the effectiveness of lights. Against someone with street light adapted vision, your light will maybe give you a split second advantage, if any. And probably very little advantage for the 2 cell verisions of the surefires. They're bright, but not blindingly bright. At most, it will probably just cause the attacker to divert his eyes for just a millisecond, but he won't be helplessly blinded.

If you want to just buy a really cool flashlight to use as a flashlight, then i say go for it. <img src="/images/graemlins/wink.gif" alt="" /> If you were serious about relying on this as self defense, I'd reconsider, because it will probably disappoint you. There is a very large selection of 2 cell 6V lights on the market. If you want to just try one out, the Dorcy or brinkmann 2x123 lights are just as bright as the E2 and can be found for about $10-$15. Of course it's not as nice as surefire, but it will be a cheap introduction into these lights. Generally, for an incandescent light, the brightness is proportional to the number of cells (volts). Among different manufacturers, you probably won't notice a difference in brightness among lights using similar batteries