I have used this on a work machine for around a month

http://www.windowsonecare.com/

Currently this is only offered to U.S. customers, but I made up a U.S. address and managed to install it without too much fuss. The application appears to run on .NET Framework 2.0 - after installing I was prompted to install a framework security patch. OneCare comes with its own firewall so Windows Firewall is disabled.

I installed the application on a development machine and found the firewall to be intrusive - on first impression it seems to block on program name and timestamp, but after hardcoding the version number of a test application in assemblyinfo.cs to 1.0.0.0, I was still having to allow access each time after a build - I assume a timestamp is used (see duplicates below). Therefore when I am coding, I tend to temporarily disable the firewall.

Apart from this inconvenience, the service is unobtrusive, although some are less than impressed with the quality of the antivirus module

http://antivirus.about.com/b/a/223994.htm

http://www.agnitum.com/news/securityinsight/issues/june2006

The application is installed as 3 separate services, "Windows Live OneCare", "Windows Live Messenger" and "Windows Defender". I'm not sure why this can't be one application. Furthermore, if I were to accidentally uninstall Windows Defender, there is no option to repair application in "Add or Remove Programs", so the only option is to reinstall - it appears a bit of a rush job.

The antivirus and antispyware update separately, although the antispyware seemes to be unable to update on my work machine - probably a proxy issue but where is the configuration?

To summarise, the product is cheap at $49 for 3 machines, but I think requires more work before I would recommend it.

I am looking forward to Microsoft Forefront Client security (formerly known as Microsoft Client protection) to see if this is any better

http://www.noelwatson.com/blog/PermaLink,guid,01408e24-4d48-44f8-868d-8766b6ff67c3.aspx