In every production environment, I have setup and installed Symantec Norton Corporate AV 7.x for the entire network, NT, Novell, 9x, etc. The product costs less than Crapafee and is much better at catching viruses. I have never been a big fan with InnoculanIT. I have had to many issues with the product crashing the servers (both Novell and NT).
The centralized manageability with Symantec by far is the best way to go. Plus, the client software is totaly scriptable and if you have SMS, you can roll it out better than any of the other AV programs.
Let me know if you have any more specific issues/questions.