This free-of-charge product, ‘Freeraser’:
http://codyssey.com/products/freeraser.html
appears to be quite good for files. It’s GUI, and offers three levels of security. This one:
http://technet.microsoft.com/en-us/sysinternals/bb897443.aspx
is from Microsoft, it’s command-line, and will do files, folders, and whole drives by letter.