Doctor Who is a great collection that includes 8 high quality icons inspired by the longest running sci-fi show on TV.
Every volume (disk), application, file, and folder on your Mac is represented by an icon. Volume icons tend to look like the item that they represent, for example, your hard disk looks like a hard drive, CDs and DVDs look like discs, and removable drives look like removable drives.
Doctor Who icon set allows you to give an original touch to your desktop no matter the file types or applications you choose to associate.
To learn mode about changing your default Mac OS X icons you can access the Apple Support page HERE.