So, I'm guessing nvidia has won the GPU bid for the Steam box? It makes sense from a Linux driver standpoint and their work in LAN remote display tech.
I was thinking about this when I was reading the article. nVidia does currently have better Linux support so it would seem like that's the GPU maker they'd opt for but it isn't that easy. It's a lot easier - and smarter, I feel - to go with hardware that's at least somewhat comparable to the next gen consoles, which would likely point to AMD. Getting AMD to fix their Linux support is a lot easier than getting a world full of developers to optimize for a completely different set of hardware. Having the hardware of all next gen consoles relatively similar removes a lot of headache for developers and makes cross platform games much easier, thus allowing Steam to leverage its superior distribution system.
I guess we'll see. I can tell you it's a lot more to consider than just which drivers are better for Linux today. I'm sure if AMD were told they'd be passed up in a SteamBox they'd quickly get working on their Linux compatibility. Likewise, I'm sure nVidia is looking to distance themselves and at least try to get a single console win this coming generation.