Your signature says "patrolman" so I'm going to assume you're a police officer and looking for a duty light.
I would go with 2 AA simply because you don't need to conceal your light and it gives a LOT more power compared to 1AA.
Now for some options:
* The brightest 2AA light currently is the
Eagletac P10A2. It has two modes, one general use 60 lumen mode which lasts 8 hours on a set of good rechargeable AA cells (a lot less runtime on alkalines though, they pack a lot less power). It also has a super bright 220 lumens mode which will last 1.5 hours. Switching modes is done by twisting the head, on/off is done by clicking the switch. It has more of a general use beam, this is not a crazy thrower. Some of the members here who bought it report that the lense breaks quite easy when you drop the light, but Eagletac has sent them a replacement without any hassle. The rest of the light is extremely sturdy.
* The best throwing 2AA light currently is the
Fenix TK20. It has the same user interface of the Eagletac P10A2 (all night general use mode and hour and a half seering bright mode). It has a very throwy beam with a sidespill which is only useable for nearby use. It is extremely sturdy. No reported issues. You can get it with a grey or a yellow grip (respectively stealth and tactical looking or easily seen when dropped).
I have given you the links to the sites on which 4sevens sells these lights. He has a discount code for candlepowerforums members (cpf8 I think) which gives you 8% off and standard shipping is included in his prices. He also as a good customer service, no problems when your light malfucntions and you want to replace/ return it. Depending on your location you may be able to find them cheaper somewhere else tough.
I personally would not consider the rest of the Fenix, Nitecore or Olight line because their user interfaces are too difficult for in high stress situations. Counting clicks becomes very difficult when adrinaline is rushing trough your veins. There are people in law enforcement who don't mind this, there are others who follow my line of thinking. The two lights above are respectively the brightest and the best thrower available and the top of the line in 2AA lights in my opinion. They are both sturdy to the point of over-engineered and they both have an easy tactical user interface. The brightness difference between the Eagletac and the Fenix won't be very noticeable, when choosing, look at the beam. TK20 = narrow, far reaching beam to spot in the trees 100 yards ahead with useable spill to light up the ground before your feet, P10A2 = wider beam, lighting up a whole backyard.
If you buy an LED AA light you need to run it on rechargeables. The difference in both output and runtime is very significant. The new low self discharge cells hold 80 % of their charge after a year on the shelf. Combine these with a smart charger (no need for top of the line, any decent charger which automatically stops charging when the cells are full will do) and you will have free light for years to come.
There are a lot of options, study them all carefully and think about it before you choose. Your light is a very important piece of your gear so you need to be able to count on it. If you have any questions, feel free to ask them if you can't find the answer.
