Windows, as an out-of-the-box O/S, deserves its bad rap for security, however, it really doesn't take much effort to make it secure. A solid firewall mainly. Anti-virus and anti-spyware are helpful too of course. I do not use IE as my main browser mainly for security concerns, however, once you have established a secure connection, there is really very little that can go wrong, provided that you are connected to the correct site (not the fault of the O/S or browser if you are not) and that you aren't really hacked already (such as someone having placed a keylogger on your machine.)
One of the things the OP and others don't get is that Mac and Linux, despite their hype, also have security problems all their own (
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The bottom-line for security, across all platforms, is that a system is only as secure as the user makes it. A high percentage of security issues are caused by user carelessness (installing software from unknown source, using file-sharing software or hacked software, not updating, knowing how to properly use the firewall, etc.) Ultimately, a Windows system can be secured and protected quite well.
The main way security is breached is low-tech. Sometimes people are tricked into installing spyware-laden software on their systems. Phishing/spoofing schemes are also growing problem and have nothing to do with O/S but with user care.
Again, it is largely the user who determines if he or she falls victim to these problems.