I'm giving my support to this suggestion.
Vorob's idea is also good, especially for those of us with several hard drives.
A personal wish for me is to be able to set aside certain areas of the disc for special purposes. For example a 10-15 MB extra free space next to large files prone to editing, like those huge texture files used by Steam games. Then you won't have to rewrite a full 2 GB file, just simply rearrange it a little. Also set aside a given area of the disc for internet cache for the individual browsers, so that the fragmented files won't go and settle all over my harddrive. Then they will be defragmented in one small part of the disc and be easy to defragment.
It would also be awesome if you could add the option to defrag folders. For example image galleries would benefit for this, if the reader doesn't have to jump over half the disc when fetching the next image.
