Holy cow, I wrote a book!
A customer wanted to know how they could improve the security
of USB thumb drives in their organization.
Specifically, they wanted to block access to removable
media devices (primarily USB thumb drives), but provide
a list of exceptions for specific thumb drives.
Fortunately, there's a whitepaper that covers exactly this topic
and explains how to set up your policies to accomplish this.
Step-By-Step Guide to Controlling Device Installation Using Group Policy