A while back I mentioned the list of Windows 7 Anti Virus partners which was way back during the RC I think. Well we have updated the list at http://www.microsoft.com/UK/windows/antivirus-partners/windows-7.aspx and it now includes (in no particular order):
The companies listed above provide consumer security software that is compatible with Windows 7. Just click the company name to see the Windows 7-compatible product they offer. For business security software that is compatible with Windows 7, please visit the Windows 7 Compatibility Center or contact your security vendor of choice.
We have also updated the Windows Vista and Windows XP list as well
I wanted to add to my previous comment, I am looking for 3rd party reviews for less-famous, higher-rated antivirus software compatible with Windows 7. I am looking for antivirus software that works best on computers in a medical environment.