This question from an American visitor via email (you know who you are!).
I hope you don't seriously expect me to count them all? I can tell you that as of 24 March 2008 there are over 160 battery details pages, which means over 160 "type" listings, and that the first section (general consumer types) has around 1000 cross referenced entries alone!
As it's being added to and amended weekly the best answer I can give you is, if you really need to know, go to the Battery Equivalents page and count them for yourself! (If you have the time).