The power of the middle-click just increased.  Using Taskbar Shuffle, you can now close windows from the taskbar by middle-clicking their tab, but that's not the main draw to Taskbar Shuffle.  This utility is all about making the taskbar behave like you want it to.  You can set the taskbar to group tabs together without collapsing them (my favorite setting), but once the tab is created you can drag taskbar items to the exact order of you liking.  For other taskbar tips, check out control-clicking and file-dragging.