I was finally able to convince my sister to make the switch to GNU/Linux a few months back and I am pleased to say that she is still happily chugging along with it.
She is not computer savvy and was initially being worried that her pictures and other files would not be accessible under an operating system other than Microsoft Windows. I installed Ubuntu on her machine and showed her all of the basics. I was kind of surprised at how quickly she her fondness for the operating system grew.
She uses Ubuntu exclusively and has had nothing but praises for it since it was installed. It was also nice to discover that she has even begun to spread the word about GNU/Linux.
I will probably introduce her to Arch Linux and Slackware later down the road when she feel that she is finally ready to try another distribution. I should also purchase a nice Tux plushie for her sometime. ;)