Is converting a good idea?
Converting these people won't help them and it won't help you or me. Realistically, "converts" will be coming from the Windows world. When you coax these people in to switching, you pull them from a world, where everybody from the Major to the town idiot uses Windows. Where drivers are written for Windows, where books are written for Windows. You drop them in a niche world, where everything is a few steps behind Windows, where hardware is not made for GNU/Linux, where there are no local users around, where knowledge has to be gained by learning yourself. In other words you dump them in an alien world, where people who merely tolerate computers are truly lost.
I know we can be very persuasive when we talk about freedom, community, low cost, high stability, acceptable security, no upgrade cycles. Trouble with that list is that it only comes to fruition when you generally muck about with computers. If your predisposition is to use a computer as an unenjoyable means to your ends, GNU/Linux won't yield any of the promised items. Using GNU/Linux in that situation will drop you in a barren world where anything you do is more complicated, time consuming and a more lonely endeavour than ever before. Your neighbor won't be able to help you. No shop has qualified staff to fix stuff for you. No crappy $5 software from the supermarket will run on your machine. The only help you have is that geeky "friend" who dumped the wasteland of GNU/Linux on you.
It will be a burden on the geeky friend as well. We always claim that Windows doesn't have a community, but that is the biggest lie in the world. Windows has the biggest community of all OSes. Everybody condemned to do computing through it, has a friend in a fellow Windows user and they all help each other to get by. When we yank them out of this real life community, we create a huge problem. These people can't handle Internet communities, this is an alien concept. The typical Windows user asks his questions to the nearest living soul, not some l33tk1d on a forum. The reality most of the time translates to the geek becoming the "help community" all on his own. This might function if the geek has angelic patience, but people can handle just so much and a non-geek is pretty draining. Non-geeks don't explore on their own, they wait until they get the solution dictated to them.
It is not that a typical Windows user is retarded, it is just that his mind works different from the ones in geeks. Different people, different skills. The problem is a lack of empathy on our behalf. We can't for a moment visualize a world where computers are alien, hostile things. Computers serve us, because we have a gut feeling about the way they function and we can beat them into submission. Non-geeks are at the mercy of those misbehaving pieces of electronic junk. Windows as the most common way of computing has the upper hand for the non-geek. They can always depend on other victims to help them. Truth be told, GNU/Linux is not better in that respect than Windows. If you can't figure out how to tame Windows, you won't be able to tame GNU/Linux. So getting the Windows user out of the realm of Windows is unduly punishing them for using something that halfway works for them.
GNU/Linux needs to depend on the curious computer users. The ones who can explore on their own. People who can ask questions on forums. The geeky people. At least we need to stop alienating entrenched Windows users. Just long enough for commercial parties to start supporting GNU/Linux as a mainstream system. We geeks can't "rescue" the 95% computer users on Windows. They outnumber us in support questions. They are ill equipped to handle computing tasks. Windows at least has the support structure in place to get them through their computing days. We only put them in agony on GNU/Linux if we can't be there 100% of the time for them to solve the trivial stuff. It might mean tolerating Windows a few decades longer, but it will mean a lot less drain on us and more time for GNU/Linux to become more refined.