I try to stick with AA (lithium & alkaline) and CR123 as much as possible. I do keep a few 9V around for the same reasons that benjamin mentioned. I also keep a few spare CR2025 batteries around for car remotes & a few D cells around for the Mag lights that I can't seem to get rid off.

The key to maintaining my battery stash is keeping some in a readily accessible location and the rest in the safe where the wife and kids can't raid the "reserve". grin
_________________________
"There is not a man of us who does not at times need a helping hand to be stretched out to him, and then shame upon him who will not stretch out the helping hand to his brother." -Theodore Roosevelt