In the last few years, I've convinced many of them to start using Firefox, Thunderbird, OOo, Gimp, and others, instead of their Microsoft counterparts.
In the past few months, I've set up many of them with dual-boot systems so they could give Ubuntu a try.
Putting all their now-familiar-with applications as prominent icons on their desktop, I've had only two complaints in the entire time.
One was "Why don't the [computer companies like Dell & HP] put this on their systems [instead of Windows]?", and "Why didn't you get me to switch sooner?"
If you get them used to using Firefox, Thunderbird, OOo & the rest on Windows, showing them how easy Linux can be is a piece of cake.
My goal is to (hopefully) get ALL of my family, friends, & coworkers using Linux - either full time, or at least as the majority of their computer time, using Windows only when they absolutely MUST do so.
Just what I've managed to do so-far has lessened my support calls down from multiple times a week, to one or two a month, just from the antivirus/scumware issues alone.