Don't let my previous comments be construed as a review of the Arc AAA. I don't have one, but everyone that I've heard from that does says it's the neatest gadget since Og banged one rock into another, and made the second one sharp.
My personal choices as far as LED lights:
On Keychain: Princeton Pulsar white (no constant one switch, but very bright), and Photon II red (good for low-light situations of some duration where color distinction is not ultra high priority).
Sometimes around neck: Inova (Emissice Energy) Microlight, white: Although larger than some of the other lights, and not any brighter, it's very flat, so lays comfortably there, and the LED is recessed into the body (similar to Photon Covert), so the light doesn't spill back into my eyes when I hold it in my mouth to look into boxes in a dark basement at work. The rubber top is also easy on my teeth.
In backpack, and "just-in-case" pack: CMG Infinity Task Light. Not the brightest, but runs a LONG time on cheap, easy to store, and easy to find batteries(AA), in addition to being bomb-proof. Plus, the green is pretty bright.
Sometimes on belt loop: ASP Sapphire. Fun, and bright, but almost too blue, and more expensive and large than is necessary.
If I had to do it again, knowing what I know now, I would replace the the Princeton Tec with a Photon I, maybe giving up a bit of brightness for the water-proofness. Or maybe one of the new III's,as though I too dislike the excessive features, I find the water-resistance appealing. Though the Inova is ok for my purposes, it's mostly extraneous, as is the Sapphire (especially the Sapphire). Perhaps I would have saved that money, and put an Arc AAA on my keychain as my white light. The Task light might be more useful to me in white, or even red, but I hadn't owned a green LED yet, so.
My next purchase(s): I'm looking hard at the Arc AAA, because of all the good reviews, and the new Princeton Tec multi-Led's look good for real flashlight use.
Joe S.