MicroCenter has Digital brand AA NiMH rechargeable batteries on sale for 1/2 price, 4 for $5. These are rated at 2000 mah (that's probably optimistic) and appear to be the standard Chinese made NiMH cells marketed under various brand names. I have had good results using NiMH cells in my GPS and also in my digital camera and cellphone.

FWIW,
CharlieP

Thanks for the tip Charlie. My camera eats the 1200 mAh in no time at all.

picked up a package this evening!

-team PEZ

Yep. I too went by MicroCenter and picked up a 4 pack of them too for $4.99, they have plenty left. I also picked up a charger for them, the prices range from a $12 model that takes 10-14 hrs to charge to a $44 model. They even had one that charges in 15 minutes, using the included double set of 15-minute rechargable NiMH batteries, I think it was $29.
I picked up a $20 unit that recharges 4 AA at a time and it came with 4 1900 mah batteries too, it charges in 7 hrs. I'm curious to see how they'll perform against alkaline. On the way home I stopped off at Wallymart in Cartersville and they have a $1 room up front...they have 4 AA alkaline packs for a buck there, so I got 5 packs to keep on hand.

I noticed the package for the NiMH batteries said to expect a 1-2% loss DAILY for a charged, stored battery! But still...slap `em in a charger, ya can't beat that!

I can't say enough how happy I am with rechargeable NiMH's. I've been using 8 of them for 2 years now. I can't imagine how many cycles I've put them through, but I've never had them poop out on me while out caching. Seem to get at least 8 hours GPS time out of every charge. Even if you only get 10 cycles out of them, they're still cheaper than alkalines.