If this were a tech site, you'd probably get panned for being a troll.
To be perfectly fair, Windows is "safe enough". There are lots of vulnerabilities along the entire networking process (including "wetware" or users), not just the operating system itself. A competent risk assessment should span the entire OSI model.
Having said that, arguments against Windows for their lack of security is not without merit. It's a large target, and except for Vista, security appears to be a design afterthought.
For typical users, the best thing you can do is to keep your OS and your security suite (anti-virus, software firewall, and anti-spyware) updated at all times. Also, don't go to any websites, download any files, or click on anything that seems suspicious.
If you want to jump off the deep end, use a clean box with a hardened OS... possibly CD-only... and have at it. Truth is, it doesn't take much for secure computing. It's just a question of how much time, effort, and usability you're willing to compromise for it.
I also admit that I haven't touched Windows since 1998... except at work, where I have no choice but to use Windows.