Leucius: Don't worry. I think with the SteamOS being Linux-based, Microsoft is going to end up providing 2 separate OS's per OS gen. Mark my words, there's going to end up being a "Gamer Edition" somewhere in there.
Arkose: Microsoft already has a gaming OS; it's called the Xbox One.
Microsoft's gaming focus is for mobile-style games on the Windows Store and Windows Phone with the big games on Xbox One. Desktop PC games don't factor into that. Steam OS is primarily meant to threaten the consoles, not PC gaming in its current form.
Steam OS could perhaps be successful enough to threaten the Xbox One but I doubt it will challenge Windows' market share among PC gamers on traditional hardware since it means sacrificing most backwards compatibility for no real benefit beyond theoretical performance gains. Windows isn't exactly bloated for gaming purposes; Windows 7 started a tradition of having each new version run faster on the same hardware (despite adding new features along the way) and now with 8/8.1 even the startup time is significantly optimised.
jjsimp: No what's going to be awful is when they stop supporting Windows 7. I don't care what abominations they have in store for us if I can keep using 7 for eternity. I will have to consider linux, but old game support has to get much better on linux.
Arkose: XP had the tentative benefit of working better on old systems with very low RAM. There is no benefit to clinging to Windows 7 since Windows 8 runs better on the same hardware.
The interface isn't even a valid concern. Install Windows 8.1, set to boot to desktop, install
Classic Shell if you really must, and you've got a faster, better Windows 7.
Windows 7 must not become the next XP, especially among PC gamers, since there is no valid reason for not upgrading to at least Windows 8.1 prior to Windows 7's support ending.
I hear what you're saying... But I must respectfully disagree. I have games that don't work on Win 8/8.1 that DO work on 7, and gaming performance in the games I have tested was better on 7 than on 8 (Skyrim, lotro, DDO, and Rift to name a few)
EDIT: Not to mention 8's incessant app updating and windows update both leeching bandwidth constantly.