Windows only: In addition to reording your Windows taskbar items, previously mentioned Taskbar Shuffle can now reorder your system tray icons as well.
As much as I liked previous versions of Taskbar Shuffle, its footprint always seemed a little too big to gain startup privileges.
After taking a look at the latest, though—which includes taskbar reordering, system tray reordering (by holding Ctrl while dragging), and middle-click window button closing—Taskbar Shuffle has more than proved itself worth the 6MB memory footprint its uses.
If you’re obsessive about organizing your taskbar, the free, Windows-only Taskbar Shuffle is a must-have.

Taskbar Shuffle [Home of the Nerd Cave]