Softpedia reports
Steam is the world's largest digital game distribution platform, supporting all major operating systems, including Microsoft Windows, Mac OS X, and GNU/Linux or SteamOS, Valve's own distribution derived from the acclaimed Debian GNU/Linux OS.
[...] There are approximately 6,500 titles in the Steam library. Almost all of them are being supported on the Microsoft Windows platform, a little over 2,300 have support for the Mac OS X operating system, and 1,500 titles offer support for Valve's SteamOS and any other GNU/Linux distribution out there.
[...] Even more good news: [...] Many other games will have support for the Linux platform soon, mainly because Valve will finally release its Steam Machines gaming console / personal computer in November, which will be powered by the company's Debian-based SteamOS GNU/Linux operating system.
(Score: 2) by VLM on Monday September 21 2015, @09:43PM
If your prefer using the mouse, you can either buy a cheap Windows computer, or build a Steam box.
Geeze. Doesn't have to be that hard. For 15+ years I've had a drive tray in my main machine and I swap in the drive/OS I want. Used to be PATA now SATA. Used to be spinning rust now SSD. Its pretty cheap. With the rise of "home raid arrays" this gear it cheaper and more available than ever.
On the shelf I have FreeBSD, Debian Linux, windows 7, Windows XP and I use them in about that order. I have some weird hardware like eprom burners and the like that only run under windows or even more specifically winXP, thats about all I do with those. Minecraft works fine on freebsd, I mostly use feedthebeast on linux out of laziness in setting it up. I also run dwarf fortress and factorio on linux, again no reason other than laziness about setting up on freebsd.
Anyway it makes life very easy.
You can wire up two drive bays and insert one boot drive and then "do stuff" to the second drive with little effort, which can be fun. At one point I had three PATA bays so I could do "dumb" things like boot linux and copy olddrive to newdrive, thus using all three slots. Some weird / old BIOS get all wound up about drives being shuffled around or disappearing; not so much recently.
WRT my "home directory" that used to live on openafs but there were some PITA things and freebsd is not 100% stable with openafs so back to legacy NFS home dirs. Works pretty well across multiple OS. I don't use windows enough to concern myself with mounting NFS home dirs on windows but presumably its possible somehow.