Visual preview of windows

This would be very helpful.  Something akin to the mouse-over of the windows in the tray.  Sometimes you store the look and layout of the page in your memory as a way to find it in the future without paying much attention to the page's title.  This is more efficient than trying to remember the title of every window.  Sometimes the windows don't have the most descriptive titles, or different looking windows may have similar titles.  Going through and typing a comment for each window is quite inefficient too.

I'm not sure what the best way to implement this is.  Maybe show a picture in a tooltip when you mouse-over each list item, maybe a new view entirely which shows a picture of all windows.  Another idea is a menu-like system, similar to the task bar in windows 7 where if you mouse-over a window, a menu showing pictures of each tab shows up.  Humans seem to do well with sorting things to tree-like structures such as this so I think it would be easy to navigate.