But the Chinese hacks were a different breed altogether, they weren't directed at Windows OS, they were directed at Goggle the company. The only way to protect yourself from such a thing is the use the most secure OS, switching to any other is little more than security through obscurity.
As soon as über-targeted social exploits are being performed, "the most secure OS" doesn't really help you that much. Most have at least local privilege escalation exploits, and considering that (afaik) IE6-specific vulnerabilities were used, one would have to assume the attackers had a pretty darn good idea about the target systems...