You may still have some SanDisk Cruzer USB thumb drives around that have a pre-configured U3 partition.
When you insert these thumb drives, it mounts not one, but two removable drives: a U3 CD-Drive and the removable disk. For some reason that seems to annoy or bother some people.
Getting rid of the U3 partition is not hard, but you cannot do it simply by trying to delete or reformat the USB stick. Simply go to the SanDisk web site and download the Laun chPad Removal file containing their U3 Uninstaller Tool, unzip the file and run it.
It will automatically locate your Cruzer thumb drive, give you the option to backup/restore any data on the thumb drive, and then delete the U3 partition. You may want to reformat the thumb drive, especially if you want it to be an NTFS file system.