The EverLED is a relatively inexpensive drop-in that gives a MUCH better beam than stock, and will run 24 hours on two fresh D cells.
I wanted something I could leave with the family during emergencies, hurricanes, etc.; since I'll be out in the middle of it (at least until I retire; soon, now...) and will have all my lights with me.
The EverLED turns the wan 2D MagLite beam into a bright white, useful beam. Adjusted down to spot, it has a surprising amout of "throw". Adjusted wide open, it makes an excellent candle, lantern, etc., when you stand the light on its tail cap.
We have other lights that see everyday use; the MagLite 2D/EverLED combo stays in the closet next to a box of a dozen fresh batteries. While I would not hesitate to utilize this combo as an around-the-house general purpose light, I have others that are smaller and easier to handle. But that MagLite is there if I need it.
Similar to your situation, I found myself with a brand-new 2D Mag and absolutely no use for it. I have seen many of these in the hands of fellow cops and have been uniformly unimpressed. With the exception of the ARC AAA, every other light I have out-performs a stock 2D Mag.
The EverLED module makes a completely new animal out of a MagLite. While all of these mods featuring PVC pipe, dimmers, Fat Man drivers(?), etc., are interesting, they are a bit out of reach for those of us who are not quite so immersed in the game... /ubbthreads/images/graemlins/smile.gif
The EverLED makes it easy; I have been very pleased with mine.