T3Desk is a freeware which lets you preview all your open Windows in a 3D like style. It can be called as an Alt-Tab replacement but it lets you arrange the open and minimized windows in 3D style. Now instead of minimizing your windows to the taskbar, you can arrange them on your desktop in a 3D like environment where you can flip and zoom between them. The program also makes use of the Aero feature if you use it on Windows Vista and Windows 7.
To minimize a window 3D style, simply right click on the minimize icon instead of the usual left click. Instead of being minimized to to the desktop, the window will remain inactive on your desktop in a 3D style fashion. You can drag and rearrange them across various positions of the screen. The windows that you minimize using this tool will also remain grouped in a T3 icon on the taskbar. Hover over it and it will give you a preview of all the windows that have been minimized. You can customize lot of setting like the transparency, zoom level, perspective settings, initial rotation, animations and lots more. You can also customize a number of hotkeys which you can use to quickly minimize all your open windows in a single button press. The transition effects can also be customized to suit your liking.
Unlike other applications of such type, the program has a low memory consumption and it worked fine on my Windows 7 without any issues. The program is a freeware and works on almost all the version of Windows. However, if you are on Windows 7 and Windows Vista, you will really love it with Aero.