Windows XP only: The good news is, Shock Aero 3D is a free, easy-to-install app for Windows XP that gives you the same kind of 3D window-shuffling task switcher that Windows has with Flip 3D. The not-so-great news is that it's not exactly a full replacement. The visual effects are both fast and pretty similar-looking, but you have to click on Shock's taskbar icon to flip through windows, rather than just simply Win+Tab-ing until you hit what you want. For those seeking a little more flash while they're still in XP, Shock Aero 3D sits nicely next to other XP "upgrades" like Vista cursors and a Vista-styled Start menu. Shock Aero 3D is a free download for Windows XP only.