Valve has been working on a console. I don't think Valve brand hardware is the big deal. The big deal to me is that it establishes a minimum standard of hardware. Right now, many PC games are limited by what the PS3/Xbox360 can output, just because they are ported pretty directly to the PC.
With a minimum standard ("This PC's hardware runs Steam Level 1 games." for example), a slim quick-to-boot operating system, and a leaked app store style category system (showed up on Steam Mobile), I can easily see "Boots into Games by Valve" in the future.
You can easily imagine Gabe Newell's latest comments on Windows 8 (it's not good) plus Steam for Linux tying together. If Valve were to release "SteamOS" on "Steam Hardware Level" performance hardware, it could make PC gaming a lot easier for a lot of people. Maybe he is just protecting himself from Windows 8 being a massive failure. That alone is a smart move.
You'd get all of the advantages of consoles (the software doesn't break) with the advantages of PCs (openness). The fact is, even with a minimum hardware standard, the OS (and all of the cruft installed on it) can greatly affect game performance.
I expect that in near future we'll hear about virtualization (possibly even GPU virt) and/or an operating system from Valve.
This is all conjecture but what it boils down to is that one of the biggest challenges for PC gaming is that it's not as easy to get into as console gaming. I think Valve is actively trying to solve that.
