For all you power users, try Windows Classic Shell for W7
Welcome to Classic Shell
I don't use the Classic Explorer really though it IS good (Marko Savolainen's "CubicExplorer" [totally free] -
Cubic Reality Software - has most of 'em beat as a file manager) but the highly customisable Start menu is a real winner.
At last I can group similar apps and utilities together and not have to trawl through Program Files to find stuff. I know this isn't a problem for most people, who only use a half-dozen apps which they can pin to the Start Menu, but if you use a lot of different apps it can get very tedious.
Grouping apps and getting proper cascading menus is a bit of shlep ("Only Administrators can move files here!") but it only took me an hour or so to get organised and now life is so much easier.
Mac
[FreeBSD, MEPIS Linux, OpenSolaris, Mac Snow Leopard, Scientific Linux, Linux Mint, Windows 7 Pro, Windows XP SP3]