Microsoft is not eliminating the need for anti-virus products. What they are doing is locking the Kernel, most virus' do not embed themselves in the Kernel but because anti-virus products do it allows them to destroy the virus' even if they are running process.
Windows XP has suffered many security attacks and I can't think of any that have got on to the computer because the Kernel was open, just some particularly nasty ones that take over the Kernel when they do, which if you have proper security precautions shouldn't happen. I completely do not trust Microsoft to be the only company to run security on Vista, I believe some kind of security API needs opening for Vista so that other anti-virus programs can work on Vista as well.
If Vista eliminated the need for Virus scanners that would be brilliant, but Microsoft don't seem to think that will be the case otherwise they wouldn't be packing Vista with their own anti-Virus program. Instead they just want to take over the market and are using their OS to kill off other companies.
