Okay so as I was saying yesterday, where I work is approaching linux, so I decided what would be a good test? to try it on people who don't know what Linux is.
Okay so this was tested on both my girlfriend and her dad, the test bed was an old dell desktop, single core 3Ghz 1GB RAM 80GB HDD nothing amazing by any standards, I installed Zorin OS 8 /w XP desktop design.
They had never used Linux before outside of android, and there PC had a boot race with mine once (Linux v Windows) so they where as new as they come.
I left the PC running with Zorin OS, and let them roam free on it, see what they could do and they where rather impressed by it, the fact they can do everything that a standard user needs, without worrying about Anti-virus programs and security issues, Without 200+ updates that will take hours to install etc. (I did use apt-get update/upgrade before they tried)
Lets say this, the XP machines her dad sells are now been replaced with Linux, he says he will still sell vista though (Sigh) but you got to offer them something. (He only sells this because he has no w7/w8 licenses) some will be going with Zorin Core, others with Ultimate depending on power of the system.
So yes, if you wish to convert someone you know to linux and they are hardcore windows users, just show them it, chances are they will be impressed, don't go for anything too advanced such as Arch or Gentoo, just something basic.
And don't be surprised if you get this question "What about drivers" lol, as we all know, if there is no main driver for it, someone has made an open source one and its already in the kernel.
A list of which distros to replace what Windows system.
XP - Lubuntu, Linux Lite, Zorin OS 8 Core, Vector Linux, Arch, Gentoo
Vista - Zorin OS 8 Ultimate, Manjaro, Sabayon XFCE, OpenSUSE, Fedora
If your PC is from the W7 age or above, you wont have an issue running something really heavy such as Ubuntu with GNOME or KDE.