@Moriendor (and zakhal): Yeah, why waste time actually reading about something when you can just immediately assume the worst and whine about it? Also, try to remember that Valve are not your friends, they're a company. They make products you like and products you buy, but that doesn't mean they owe you a scrap of loyalty. That doesn't make them evil or sickening. It makes them a company.
As Zloth says, what we know about Steam OS is that it's a PC OS -- and quite an open OS, in that's free to install and free to licence -- running on a PC. If -- or more likely "when" -- the SteamBox is announced, it will almost certainly be a PC, capable of running Windows, etc.
Now there probably is a discussion to be had about whether this is the thin end of the wedge towards some kind of "closed console," and whether it's likely to lead to develops requiring a controller (I personally don't see either happening in the short to medium term). But the out-of-hand dismissal of anything new or different is a bit sad. You know what will definitely signal the death of PC gaming? If it never evolves or changes. Take that from a dedicated Spectrum and Amiga fanboi!