Symantec Endpoit vs. Corp. Anitvirus Software?

We are looking for protection of our computers from outside threats (internet, email, etc.) but also inside threats (i.e. our students or teachers or staff bring in a thumb drive with a virus).  We are not sure which product would be better to secure us from these two major issues.  We have been looking at Symantec Endpoint and also the Corp. Anitvirus software, is one better for our purposes?

Symantec has an article on their website comparing Corporate Edition with Endpoint.

I would be interested to know which version you decide on.

We currently use Symantec AV Corp Edition.  There is a lot of over-head, I would be interested in seeing how much over-head is in Endpoint.  To me it would drag things worse.  Aren't thumb drives a pain in the neck to keep an eye on? 

Gary, now that you mention it, thumb drives ARE a big pain in the bum.  There's a lot of software out there that is supposed to prevent users from being able to use thumb drives.  I'm sure its possible, actually - but I don't think its as hard as they are making it out to be.  USB drives have UUIDs...  I knew this on an instinctual level but actually learned about looking them up when I as trying to get some usb drives working in a Linux environment.  And because I wanted these particular drives to always be mounted in the same folder, but could not always clearly indicate which device they'd be called (sdb1, sdc1, sdd1, etc), I found that I could specify them in Linux by their UUID, and thus always mount each USB drive to the same folder.  Now, there must be a way to set up Windows to disallow unapproved UUIDs from being allowed access to the operating system.