<a target=new class=ftalternatingbarlinklarge href="http://support.microsoft.com/default.aspx?scid=kb;en-us;302686">When you choose to run a regular format on a volume, files are removed from the volume you are formatting and the hard disk is then scanned for bad sectors. The scan for bad sectors is responsible for the majority of the time it takes to format a volume.
If you choose the Quick format option, format removes files from the partition, but does not scan the disk for bad sectors. This option should only be used if your hard disk has been previously formatted and you are sure that your hard disk is not damaged.
If you installed Windows on a partition that was formatted by using the Quick format option, you can also check your disk by using the chkdsk /r command after the installation of Windows has completed.</a>
The ONLY difference is "Normal" checks for bad sectors and "Quick" does not. BOTH remove all files.
Save "Normal" for new drives, and drives you are not familiar with. Otherwise you are just wasting your time.