Improve the recycle bin interface
The recycle bin interface is incredibly primitive and really only useful if you need to recover a file or two that you've deleted very recently. If you're looking to restore something that was accidentally deleted a while back and not noticed, then it's very difficult as you have to scroll through many deleted files. For starters, there should be a search/filter by file name. For more complex tasks, the user interface as used by most backup solutions (like DPM) would be helpful, e.g. recover all files deleted from a specific folder.
I would vote for this.