My manager want to install some latest antivirus for all the PCs inside our company due to some heavy virus attack few months back. So, he want me to look for the best antivirus software as now there a few choice like norton, AVG, Mc... So, I need some advice of which software to buy.

BTW, we plan to intall for our server also. My friends advice me to get a 'filter'. Something like a hardware that act like a firewall or something... But, that like only for mail only.

Any good suggetion?