Bitcoin is not just for Linux users
Think about whether you fancy yourself as part of the "technological ruling elite". Bitcoin has nothing to do with any OS. All people should be able to freely use and enjoy this technological advancement. Different OS's represent different user groups, and those groups may differ from you in many ways. They probably differ in technical expertise from yourself. The solution isn't to make them just like you....
I disagree. Bitcoin is in its early stages and not idiot proof at all. Currently, we only have the core functionality: sending coins from your computer to somebody else. All the convenience functions like security are missing and whoever wants to use Bitcoins right now needs to understand that it's her own responsibility to keep them safe.
You need to understand the average computer user here: To them, having an insecure Windows machine is no big deal: It doesn't matter that their email account got hacked and is sending spam because they used an insecure password, they just get a new email address with another insecure password. It doesn't matter that their computer becomes part of a botnet and gets a lot of malware thus running slower and slower: The average computer user will just say "Well, computers get slower over time, I just have to buy a new one or hand mine over to my neighborhood geek to fix it". Also, it doesn't matter if their HDD breaks. They don't have backups, but the files on their computer weren't important to them anyways and all their important holiday photos are on facebook anyways.
Now, the important thing here is that Bitcoin is different from all these other problems: Contrast it to email: The whole point of email is to allow you to communicate. If your account gets cracked and is used for spam, you can create another email address and continue with what it's about: communication.
The point of Bitcoin is to move money around. The really big difference is that getting hacked here actually destroys the whole point of Bitcoin since it's actually a loss to you: It's not like "Oh, my computer is slow, I'll just get it fixed", if your wallet gets stolen it's not possible to just create a new one: You actually lost that money and no friendly neighborhood geek can fix that for you.
What I'm trying to say is that AT THE MOMENT Bitcoin is not suitable for your average "I use Windows and I don't care that it's insecure" user. Because Bitcoin is in it's early stages, any serious business with it should only be done in a secure environment, namely a secure OS. If anything, for convenience you should only keep a very small amount of Bitcoins on your Windows machine, but not more than you can afford to lose.
I think that in the future, Bitcoin will become fool proof; the average user can just use an online wallet in combination with a RSA token, just like online banking works right now. But we aren't there yet and saying "Don't be elitist, every idiot should be using Bitcoins today!" does more harm than good.
By the way, using Linux is no big deal: even a chicken can install it if you place enough seeds on the ENTER key and you can just install it parallel to Windows: When you turn on your computer you'll get a little selection window where you can choose to either start Windows or Ubuntu. Also, during install, Ubuntu offers you to encrypt your Ubuntu partition, which is exactly what you want to keep your money safe. Use Windows for your pocket money and Ubuntu for your savings account.