I'm new at this, but this is how it appears that our addiction usually plays out...
Prioritized Flashaholic Checklist:
1. EDC: should be something that will cover 90% of your flashlight needs, so multi-mode or variable output is an absolute must. Runtime is not a priority since you'll use the light often enough to know when it's running low. You'll run rechargeable batteries in your EDC and top them off regularly, but it's handy if the EDC takes a common cell size. Should be able to get max output quickly and easily in a self-defense scenario. The D10 is an excellent EDC and meets all these criteria.
2. Emergency flashlights: cheap flashlights with expensive batteries that you stash in each car, the garage, under the kitchen and bathroom sinks, etc. These are the flashlights that you don't use very often, but when you need them, they have to work. This means you put batteries that won't leak and have a long shelf life (any lithium primary cell (button, 123, L9[12]) is good. LSD rechargeables will do if you have the discipline to check them a couple of times each year and don't live where it gets especially cold). Runtime is more important than brightness. Simple UIs are preferred over the more complicated UIs of premium lights because these are the lights you'll loan to friends and family members (you will probably still use your EDC in an emergency, cannabalizing batteries from the emergency flashlights as needed...your EDC on low mode will probably out last the emergency flashlights anyways).
3. "Old Reliable": something with decent output and throw and long runtime like a 4-6D maglite with a decent LED dropin. This is the "security blanket" flashlight for when it's comforting to be holding something heavy and bright. It's probably not for you (you're packing, right?) as much as it's for your kids, spouse, etc. Also handy for looking for pets/kids outside late at night.
These are the basics. Note that only the EDC is really intended to satisfy your needs...the emergency lights and "Old Reliable" are mostly for those around you who don't have their own EDC. However, catagories 2 and 3 are great cover for your addiction since almost any light you purchase can be justified by claiming it's either a 2 or 3 if you don't already have a better reason.
Beyond that, catagories of interest include:
* backup EDC: not quite as capable as your EDC, but generally smaller. Usually small enough to fit comfortably in a pocket or on a keyring. Suitable for gift giving if you're trying to recruit another flashaholic or you're tired of your wife borrowing your EDC all the time.
* thrower EDC: not as versatile as your EDC, but generally brighter and better than your EDC at illuminating distant objects. Also generally bigger with more battery capacity than your EDC. Usually carried hidden in a coat pocket or, if your EDC isn't already on your belt, in a belt holster.
* monster thrower: a flashlight that you only bring with you if you know you're gonna use it (if only to impress your friends). Rediculous output is expected. Nice if you can run it on D cells, but more exotic batteries are often required.
* Tactical lights: something you hold in one hand when the Glock is in the other (unless it's already mounted on the Glock)
* Toys: pocket rockets (tiny flashlights modded for rediculous output for short periods of time because of battery and heat considerations), novelty UI flashlights, etc. Lights you don't need for anything in particular, but they're cool, so you buy them anyway. Once the novelty wears off, they generally become emergency lights or gifts.
Accessories to your addiction:
* Rechargeable batteries with decent charger. Don't skimp on your charger...
* battery organizer (with notebook for keeping tabs on your rechargeables...)
* soldering station and dremel for repairs and mods...
* paypal account...
Please let me know if I've missed something.
--flatline