The typical PC user uses a web browser, an office suite and videogames. With Chrome you have an excellent web browser regardless of OS; LibreOffice is fine for many users and it's interface is similar to that of Office pre-Ribbon, which many appreciate. Games have been a painful issue, but with browser-based games and Valve porting to Linux it's getting really better.
I believe it's a matter of time until users begin questioning the Microsoft tax when they can get a useful OS sans viruses and malware for free.
You sound like mac users 5 years ago. There are viruses and malware for linux systems today. As the market share goes up, so too will the attacks.
I don't mean to say that Linux is totally immune from malicious software, but it's a much harder target. You're in the position of having to either get malicious software into the repositories, convince users to do something arcane and atypical with binaries downloaded from the internet, or exploit security vulnerabilities in installed software on an OS with a package manager that auto-updates everything to the latest patch on a regular basis. None of those is anywhere near as easy as "click here to see Anna Kournikova naked" or exploiting known Java vulnerabilities that Apple was kind enough to leave unpatched for like a year.
Funny, I'm getting ready to upgrade my gaming PC from XP to Win 7 soon.