I have a rich and varied battery collection.

AAs: I have a lot of lowish capacity NiMH AA which are virtually useless to me and which I ought to dispose of. I have a couple of eneloops AAs which live in the GPS and which I love, and I plan to get more of these because you can stockpile them charged. I have some high capacity NiMHs which are useful for holidays and the like. I have about 20 alkaline AAs which I expect to more or less consume before they expire, in odd electrical devices about the house. I have about 4 lithium AAs which I take as backup eg when skiing, but which I try to avoid actually using. Other than my GPS I don't have a lot of critical gear which uses them.

AAAs: I have these in alkaline, about 4 lithium and some NiMH. These don't get consumed much day to day; they are mostly for emergencies. I have small radios which use them, and head torches (in the Zikpa range).

123s: I have about 10 of these in lithium, mainly to feed my two Surefire torches in emergencies. I have some rechargeable ones that I don't dare use.

18650: just one of these li-Ions, to power my SF U2 when I take it for walks.

Cr2:I have 2 Li-Ion and one lithium, to power my Orb Raw. This is the torch I use most often.

2032: I have a bunch of these spare to go in various coin-cell lights. Mostly they came out of cheap or free fauxtons.

LR6 9v: I have 2 of these spare; I only use them in fire alarms.

Custom: I have a spare battery for my camera and another for my phone, both of which are weird custom Li-Ions.