One feature missing with Windows that Microsoft refuses to add is the functionality to shuffle and reorder opened applications or programs around in the taskbar.
Fortunantly there are many utilities that "fill in" the gaps left open by Microsoft, such as Taskix that allows you to reorder buttons in the taskbar by simply dragging and dropping them in any order.
Best of all, Taskix is free and is a stand alone utility that requires no installation.
Written by Adrian Schlesinger, just download Taskix to a folder on your Computer, unzip it and double click on Taskix32.exe.
After launching Taskix, just click on the Activate button, and the utility will run in the background. If you want taskix to run when Windows starts, check the box next to Autostart with Windows.
To reorder open apps in the taskbar, just click on a button
then drag and drop it to any location you want the button to be ordered.
Taskix is a cool utility with a small memory footprint and runs on Windows XP, Windows Server 2003 or Vista. A 64 bit version is also available.