For the money you can't beat the Dorcy. It is brighter than any of the ones mentioned, at least the two I have are. I consider it a little too large for my keychain. The Arc AAA or the Sonic are about the limit for the keychain for my use.
If you are not going to use it on a keychain, the Dorcy is the best buy. It is not as nice or as well made as the Arc or Ultra G, but it does what I want it to do. It is brighter than the single AA lights mentioned, although not enough to shout about. But it only cost $6.00, and you do not have to order it.
All the lights mentioned are excellent lights. The Ultra, and the Arcs are tougher, and will last longer than the Dorcy. For the pack, and if you want a small AA light, I would go with the Ultra from countycom.com. They are good folks, provide excellent service, and the price is excellent . Find the link to their CPF specials.
I agree with you on not carrying your keys if not required. Even hunting my partner and I have always left our keys next to our trucks. It was a good thing one time.
He and his wife were scouting in the deer area, and she collapsed. He thought she had a stroke, and with his walkie talkie ham radio called town through the repeater he could reach.
We were able to get the emergency people close, but they did not have a 4x4 vehicle to get to where they needed to be. I was able to tell them where the keys to the truck were, and they found them and used the truck to get to my friends.
She had a seizure as a result of the disease which is caused by low suger in the blood. The opposite of diabetes. She did not know that she had it.
Departing from the thread, but a sidleline regarding not taking the keys with you if you don't need to.
Jerry