My Exposé (for Vista)
Here’s is an interesting app that gives you OSX’s Exposé functionality, in Windows Vista. If you press F9, or swipe your mouse to the top left corner of the screen, you get to see all your windows side by side. You can then click which window you want and that will be the selected one. You can also customize what button or which corner is used.
A nice alternative to Flip3d and Alt + Tab. It is also open source in case you wanted to learn how its done or improve on it.
Note: I had to download and install the Microsoft Visual C++ 2005 Redistributable Package to get it working.