Something I've wanted to do for a long time is be able to simply move application around on the Windows taskbar.  I go out of my way to open a certain set of applications in a particular order (Outlook first, then Opera) so they always appear on my taskbar in the same order.  When I have to close one of them it really bugs me that my applications are then out of order until I close all applications (which is rarely)

I've looked in the past for an application that can re-order applications on the taskbar like you can with tabs in Firefox and Opera and Taskbar Shuffle is the first.  All other applications I've seen have complex interfaces, rather than allowing simple dragging and dropping.  Taskbar Shuffle also allows you to close an application by clicking your middle mouse button on it.