Office:

Trend ServerProtect for all Windows Servers,
Trend Scanmail for Exchange for the email server
OfficeScan Corporate Edition for the workstations
all are configured to update everyday.

Home:

Trend PC-Cillin 2003 with POP3/SMTP mail scan enabled

Guys, don't rely on AV alone. Regularly apply necessary security patches on your OS.

Also install some form of personal firewall if your computer directly connects to the Internet.