For car emergencies have you thought about an Eternalight???
http://www.techass.com/
This light would be ideal for you, it is regulated, it runs off of 3 AA lthium bateries. Not 123's, but the lithiums have a longer shelf life than reg. alkalines. If you notice the second picture that is a magnet on the back, You can stick it to your car, and it will shine where you want it, dont worry about holding it in your mouth or armpit, while you change the flat!!! Also this light has different modes, including strobe, S.O.S., attenetion getting mode, and a few others. If you were broke down on the side of the road, you could stick the light on the trunk, put it on Attention getting mode, people would see you for two miles before they got to you!!!
The price for the EliteMax (pictured above) is 74.99, if you order be sure to get the CPF edition, which alows you to switch leds, with different colors. Please note that due to no reflector there is not a huge amount of throw. It is similar to an Inova X5, with a great amount of flood. Perfect for roadside emergencies IMO.
Even if you still want an 2x123 light, throw this in your glove box, because its worth its weight in gold just for the attention getting mode. (that you place on your with the magnet car so traffic can see you)
Go to the website and watch the Video, thats what convinced me.
Here's the link:
Video for Eternalight.
Take care,
PSM