If you've ever run your drive out of space while a long-running download is still going, the Online Tech Tips weblog writes up a simple solution to change your download location to another drive.
The solution is easy enough—just stop the torrent, change the download location to another external drive, and then move the half-finished files to the new downloads folder. Once you choose to restart the download again, uTorrent will detect the half-finished files and pick up where it left off. It's a simple solution, but might come in handy. Hit the link for the full walk-through.
How to move a half-finished download in uTorrent [Online Tech Tips]