I think that those talking about custom linux and closed systems have gotten the wrong idea.
Gabe Newell specifically said PCs - Personal Computers - that are living-room friendly (and not only Valve's own branded machines BTW) will be competing with home consoles next year.
PC means it
cannot be a locked-down system that only runs Valve's software, or a console using consumer-level x86 hardware as that would still be a console. PC means it's a platform that allows personalization and installation of consumer software - games or not.
Despite their own Linux efforts, Valve would be shooting themselves in the foot by trying to sell a Linux computer for gaming in 2013. Just look at the list of
supported Linux games. Take away all the indies and they're left with a dozen of games, and not even the Half Life series are in there.
They would be alienating almost every single PC user who purchased something from their store and it would cause a division inside their own market. I can't see that as a reasonable business tactic, as much as they want to lower Microsoft's dominance in the PC market.
Maybe if Valve start pushing Linux as a publishable platform
really hard they can come up with a Linux box in 5 years or so, but this is definitely not happening with their first Steam-branded PC coming out in 2013.
And by really hard I mean pushing for OpenGL-based engines among the developers, offering discounted prices for the Linux version of every game, pushing for better driver quality and faster releases from AMD, Intel and nVidia, etc.
I think it's going to be just a Steam-branded windows machine. I'd bet it'll be something along the lines of
Asrock's VisionX Series and Alienware's X51, maybe without an optical drive and larger in order to fit standard components with a higher TDP.
If they're smart, they can build a small-ish, high-performing and efficient machine for some $650 or less: a 128GB mSATA SSD for the OS, a 2.5" 1TB hard drive, a 4-core/4-thread or 2-core/4-thread Haswell and whatever price-equivalent of Pitcairn/GK106 might exist in Q3 2013. If they sell the hardware through the Steam store, they can probably get a high-enough volume to guarantee customized components (I think it would be hard to make a
living-room friendly PC without a low-profile graphics card, at least) at a low price. They could order most components like graphics card, motherboard and case from the same Taiwan-based PC company (Asus, MSI) to cut costs.
Despite Newell's statements about Win8, I don't think they'll have a choice, and in fact I think the OS is quite good for HTPCs. At least anything is better than Win7's piss-poor support for large-screen scaling. I know how much I suffer with it.
And then there's the fact that there are some AAA games that aren't coming to Steam, like Mass Effect 3. Valve doesn't want to deal with the anger of their PC clients not being able to play some
very important titles that aren't being sold by Steam.
Now what I think they must
really solve if they want a console-like friendly experience is the amount of publisher-specific in-game sub-sub-interfaces with specific logins. Jeez I logged into Steam, then if I launch a Microsoft-published game I also have to login into Live, so I can have the game working within the Live interface which is working within the Steam interface. Then I launch a Rockstar game, I have to login into the Rockstar Social Club so I can have the game working within the RSC within Steam. And then there's EA and Ubisoft that are constantly trying to make me go into their own marketplace to purchase DLCs when I'm playing their game, even if I'm playing the game from Steam and the DLCs are available from there.
More than driver stuff and optimization issues, I think this DRM stuff is hurting the PC gaming industry the most.