The best enterprise virus scan/internet security software is……???

I am looking for experienced opinions of the best enterpise virus scan
software for a Wndows XP/ Server 03 environment. I also want a
program that can assist me with internet monitoring over computers on
my network so we can regain some productivity without shutting down
access to the internet. I have reviewed Pearl Echo and Spectort360. Any
suggestions about these or others????