It's like some of you weren't around for the announcements or something..
There are going to be several types of Steam machines. Though my guess is that they'll pretty much be two main types with lots of custumizability options.
The first is what I personally, and most existing PC gamers with any interest in expanding their gaming into the living room would likely purchase: A streaming box. A simple, little black box that streams my PC games, near latency free, to my TV from my existing powerhouse of an SLI rig. It's not only going to do that though - it will also support streaming my music/videos and almost certianly support stuff like netflix and youtube and twitch TV, etc, etc. I wouldn't be surprised if there are some models with a passthrough for a cablebox a la Xbone for live TV support.
The second type is basically an HTPC. But it's steam branded, and probably much easier to pick up. I wouldn't be suprised if eventually you could wlak into walmart and ask for a "Steam machine" PC and have only a few options available, kaing it easier for Joe Schmoe to partake in the glory that is PC gaming.
And people, Valve are NOT a bunch of morons. They are not looking to compete with consoles head on the same year they release. It's not worth it. The Xbox brand hasn't made Microsoft ANY MONEY yet. Think about that. Even fi valve wanted to get into the console business it would be folly for them to expect a return on investment earlier than a DECADE from now. Ridiculous. You'd have to be crazy to try and compete in that space directly...
But indirectly... Well, I don't know about you guys but in 2006 80% of my friends were console only gamers. Today 100% do at least SOME gaming on the PC, with a good 75% gaming almost exclusively on their PC's.
Valve cannot compete directly with subsidized hardware and Billion dollar marketing budgets. BUT, in 3 years time, when Steam boxes are a reality, the kinks are worked out, there is wide support for Steam OS, and when you can include hardware that is 2-3 times more powerful than a "next gen" console for roughly the same price?
That sounds like the perfect time to bring in even more PC gamers into the fold, IMHO.
I think that's their plan.
First the will make PC gaming in the livingroom space a viable, easy thing to do even for Joe Schmoe, then they'll make the hardware easily and affordably available.
And those are only good things for PC gaming, IMHO.