Windows is fine, and is more secure than linux. If linux would receive the same amount of malicious attacks that windows receive, linux would become unusable and would require patches for years. The security on some of the linux distros is atrocious. Linux security is achieved through obscurity. An attacker isn't going to bother writing attacks against an OS that less than 1% of people use, and those that do use linux are likely to be highly technical.
I think you're misusing the phrase "security by obscurity". Security by obscurity means that the technical details of your system are guarded closely from potential attackers. As long as you can keep the outside world from understanding how your system works, they will be unable to exploit flaws in your system. This was a large part of Sony's strategy to keep homebrewers from getting root on the PS3 (which ultimately failed).
The phrase "Given enough eyeballs, all bugs are shallow" applies to linux because bugs (and security flaws) are not hidden, they are openly shared so that they can be recognized and fixed. Linux is the complete opposite of "security by obscurity"!