one software package.

Securewave, sure it's expensive, but it can lock down what can and can not run at the kernel level so go ahead double click on that exe it won't run unless it's on the white list.

Not to mention you can lock down the usb ports so that printers work but usb keys do not. You can lock the floppy and the cdrom. Think about it, if there is no way a virus can execute it's code then you don't even need a virus checker.