I'm curently using and I've sticked to Symantec Antivirus Corporate Edition 8.0 wich suited my needs and haven't let me down till now. The Kaspersky (at least the 5.0 version I've tested) is way more advanced than most AntiVirus software out there just for the fact that it dose look inside .zip file, inside "packeted" .exe files and so on, check out it's features page for a list, BUT the thing that sucks at it is the resources that consumes. Way to much.. The same thing I can say about McAfee 9.0 (or whatever is the latest version), Norton Antivirus 2003 and 2004, the 2005 too but at least it has an firewall thing included. BitDefender? Who are they kidding with this? I've got an utility to clean an welchia worm and it said I'm not infected when I was. Definitly SUCKS bigtime! On Windows 200 I had Notron Antivirus 7.0 Corporate Edition too and I've liked it but moved to something new. As for the others from the list I haven'te tested them too much. Sticked to what suited my needs and didn't drained my sistem out of resources.. Tha's SAV 8.0 CE (Symantec Antivirus Corporate Edition 8.0)