NOTE: This is now old. Check out the 3rd edition!
British Library Unabridged.
Containing 712 icons at a native resolution of 512×512 px.
This set is meant as sort of a catch up. It shall contain all icons from the previous primary Windows releases, plus a few more, to be released in PNG and ICO format. The ICOs have been rebuilt and now include all of the intermediary resolutions in RGBA—64×64, 96×96, &c. A few aren't actually 512, because they're status icons and stuff (generally 16×16).
The set itself will be released in the coming days. In another deviation. Or two.
(Why the gigantic preview image and lead-up? Why, because the other one is on my old account, it's out of date, and I didn't blow enough time making it, that's why!)
(The name I gave myself at the bottom reads "Samantha Wright the Blind" Well, literally it says 'right', not 'Wright,' but you get the picture.)
Also, I don't recommend clicking download unless you need to test your funky new image compression technology or something.
Maybe I should split this up into sets according to application/function... hmm... someday.
Links to various formats:
Windows (Up to and including Vista): [link]
PNG (for skinning, Gnome, etc.): [link]
Mac OS X (Up to and including Tiger): [link]
Mac OS X (Up to and including Leopard): [link]
The Leopard version should work on Tiger, but this is a) untested, b) much larger, and c) unnecessary.