I have not completely switched to Linux. I have a computer with Windows XP that I use to run Quicken and Netflix. All three of my other computers are Linux. Two with Ubuntu 12.04 and one with Mint 13/Maya.
If both Quicken and Netflix ever get their act together, then it would be no Windows for me.
You can get a cheep desktop and put Puppy Arcade on it.
It is a distro based on Puppy Linux which is based on Ubuntu.
It has a lot of games like Doom and you can play PlayStation games on it if you connect a controller. And you can also play a lot of other retro games on it.
My other computer, an HP netbook, also runs Ubuntu 12.10. I will just take my Tomtoms over to the in-laws house to update them. I already installed Tomtom Home on their machines. Tomtom Home won't work under WINE.
I switched over my HTPC hooked up in my living room to Ubuntu about 5 months ago over from Win7 and haven't looked back.
I was so impressed I switched my work PC to Ubuntu about 3 weeks ago and use Virtualbox for Win apps that I still need for work.
Biggest issue for me is that on my work machine 12.10 install CUPS is seriously broken. I can't print to anything. I had to hook up my printers to a different Win7 machine, share them, then add them to my Win7 running in VB.
Only other thing I really miss is Lightroom. I'm using Aftershot Pro but it's not as good.
I switched completely to Ubuntu and have a Win7 partition only for iTunes (iPhone backup) which I don't use very often.