Cutting out the middleman, M$ intends to cash in on the lucrative anti-virus market by cutting out the industry M$ created by shipping an OS with no inherent security for decades. “8” will include anti-virus.
Fortunately XP and “7” will be around for a decade or more so the anti-virus industry will be around a while longer. Consumers wanting a single point of failure can now choose M$ with confidence.
I recommend Debian GNU/Linux which has few problems with viruses.