avast has a removable device scan but many users do not know that he has this scan or do not have patience to stay scanning every time puts a USB or a CD in the device I suggest a real-time protection of removable devices to prevent pain head of many people
Avast already does that as it is a resident on-access scanner - if there is any activity from the USB - then those files are scanned.
Many users here also use MC Shield along side of Avast to protect USB when engaged.
http://www.mcshield.net/
+1