Thanks all for your replies. I've had a look at your suggested lights, and I think the one I'm liking the most so far is the Malkoff. Seems like a proper bit of kit.
No one doubts the build quality of Malkoff lights but it probably won't work well for your application. If you're used to a couple hours of runtime with the Fenix LD10/LD20 then the Malkoff will only last about an hour on its highest setting. And going from 25 lumens to 250 lumens is a huge step. People got by for a long time on 60 lumens and after your eyes are adjusted to night time 250 might be overkill but it depends on what type of exploring you're doing. I'd also like to add that Malkoff lights are over built. If your Fenix has lasted you 10 years and still kicking then the savings on a lesser expensive Chinese made light can be put to use in other areas, like 2 or 3 lights. The saying is two is one and one is none so having a backup light isn't a bad idea.
Summary of Modes: 3/25/250 Lumens
Approximate Runtime in modes: 100/20/1 Hours
For size comparison, here's my Zebralight SC64w HI, Convoy S2+, and Foursevens Quark Tactical QT2A-X. Manufacturer specs for the Quark lists a 138 lumen output on high for a runtime of 2.5 hours. The Zebralight lists 467 lumens for 3.2 hours, 245 lumens for 6.3 hours, and 118 lumens for 13.8 hours. There are 12 brightness levels in all but I just listed the comparable ones.
http://www.zebralight.com/SC64w-HI-18650-XHP35-Neutral-White-High-Intensity-Flashlight_p_232.html
The thing is, I've just replaced my white label Eneloop's with new ones. My white Eneloop's are from 2009 and made by Sanyo. I've been using them for ten years now. Amazing batteries. The only reason I've replaced them is because they're all beat up. The wrapping is all peeling and one has quite a substantial dent in it. Still works just fine though, but I figured it was time to replace them, so I bought some Eneloop Pro's after being so impressed with the original Sanyo's.
Take it as a loss or use them for other devices. Now that 18650 lights are readily available there's no reason not to get on the train so to speak. It's the same reason why incandescent flashlights are considered outdated by today's standards. It took me a long time to move to LEDs because of bad color rendition but LED technology has gotten a lot better since then. I now have lights that use a Nichia E21A, Nichia 219B, Nichia 219C, and Luminous SST-20. All are above 90 CRI. I still have my old SureFire G2Z and M6 incandescent lights (60 lumens and 250 lumens respectively) for the light quality and nostalgia. Also because I still like to keep lithium primary battery lights around for emergency purposes since they have a long shelf life, very low discharge rate, and can withstand extreme temperatures without degradation. They get used maybe a few minutes a year but mostly not at all.
I like AA for the same reason you do, in that they're readily available if you ever need to get hold of some in an emergency, or if you just run out when your on your travels. Plus I mostly use the lowest and the middle mode's on my flashlight, so my batteries easily last any trips I do. Its only very rarely that I need to swap out the batteries for fresh ones (I always carry 2 spare). So AA's work for me just fine.
Yes I keep them around but only because I have a 20 pack of Energizer Ultimate lithium batteries with an expiration date of 2039. The 2xAA light isn't used at all. If the thread title was, "What's the best quality flashlight for urban exploration and camping?" I would guarantee that almost no one will recommend a 2xAA light. I know it seems like I'm talking at you and not to you but if you're thinking from an engineering mindset then the application determines what materials you'll use, not the other way around.
I've Actually been out earlier exploring a few places. And thinking about lights while I was using mine highlighted how much a light with a more flood'y beam would suit me better, because most of the time I use the light for close use. I don't really have a use for a thrower as such. The only 2xAA light I can see with a flood beam is the Fenix FD20 with its focusing head. The focusing mechanism is all external though, and I'm not sure how well it will stand up to getting dirt and dust in the mechanism, given that its not designed to be dismantled for cleaning.
I think I might go for the Malkoff. Just need to wait till the come back in stock.
Have you thought about headlamps at all? It keeps both of your hands free. When I mentioned an additional flashlight for more throw, I didn't mean something for spotting objects at 100 meters but something similar to the LD20. Something to compliment a floody headlamp so if you're walking in the woods you can see the path in front of you.