My activities in Open Source have paid for our house, car, etc etc (despite there being no such thing as an "open source business model"). However, I have never really actively attempted to convert my wife, Erica, to use Linux. Mainly, I have never really felt that Gnome (the predominant desktop environment) was particularly non-technical user friendly, nor that an end-user would be able to get very many applications running in Wine. Erica uses Open Office because we use it at work. She uses Firefox, and now Chromium because she didn't like Internet Explorer and when it misbehaved it tended to take a lot of things with it. However, she has always used Windows in part because Quickbooks and Quicken only run on Windows. She's a bookkeeper by trade and these are essential tools of the trade. I do not know if GNU Cash or Turbocash is good enough but her legacy data is an issue. On her last laptop upgrade she was forced into using Vista because not all of the drivers she needed were available for Windows XP. She became frustrated with its instability. Her frustration reached the point where she asked to try Linux. I wasn't entirely encouraging but figured she could use it for Open Office.
Luckily, we have plenty of extra laptops around the office. We also have plenty of Ubuntu CDs and images available. I gave her a base installation (she probably could have done that herself). She figured out how to install Quickbooks on Wine all by herself (I think she ended up using the Codeweavers version). From there she was able to install the flash plugin, other tools and utilities. I helped her get UltraVNC installed on her old laptop and a vnc client installed on Ubuntu. For now she can access Quickbooks remotely on the old laptop (as it is known "not to work" on Wine).
Some things that I think were key to her success:
Granted, because of who I am, she's a little more likely to try Linux and Open Source Software than the average user. However, I think it really made me think how far Linux and Open Source software has come. Once she finds an acceptable alternative to Quickbooks with sufficient data-import features, she'll be well on her way to being Windows-free.