In other words, this is going to be a gaming PC that's nowhere near price competitive with consoles. To get 1080/60 on everything, you're probably going to need GTX 670/680 class hardware, at a minimum. At that point, you're at PS4 pricing before you even add a CPU, memory, motherboard, OS, or the custom enclosure. That doesn't even include a controller.
Steam Machines are going to be dead in the water unless vendors make more cost effective models. The people willing to spend $1000+ on gaming hardware probably build their own, and people buying consoles already aren't going to pay a 100% premium over current-gen console prices just to get a Steam machine.
(Hopefully, other vendors will tone down the hardware somewhat, and concentrate on bringing the systems closer to price parity with consoles -- or at least the same ballpark.)
Jumping the gun a bit there. I have a 560Ti and the only game I've played that I couldn't get 1080p/60 on with some combination of settings is Crysis 3. And that's not on Steam lol.
My point is, "plays all games at 1080p/60" is useless marketing speak and says next to nothing about the contents of the system.