I think facilitating "couch gaming" and easing the access to PC gaming for users accustomed to consoles is an important thing. However, I'm not convinced the confusing mess of Steam Machines is the right way to do it. Most of them seem terribly priced and this might just as well end up confusing that target audience rather than helping adoption and expanding PC gaming. I'm not really convinced they will succeed when the cheapest ones are $459.99 and you can't do much on them except for playing SteamOS games. Even if all new relevant games came out for them, they are significantly more expensive than the Xbox One/PS4 while possibly not even delivering a superior experience. Judging rationally, a PC in the same price range would be a better bang for your buck and permit you running all PC games.

Steam Link is an interesting gadget I think. Because of the need for an HTPC or a direct cable connection to your PC, couch gaming is still somewhat hindered by the unpractical setup. For $50 it would clock in cheaper than any HTPC and might just very well scratch that itch.

The Steam Controller is an interesting concept, but I'm not sure how well a controller deviating from the "standard" two stick layout would work in future games. Here it remains to be seen how useful and responsive it is, I guess.

Finally, SteamVR may or may not be interesting. Right now it's not clear how much that thing will cost and whether it will support operation from a sitting position at all. They seem to be going for a VR solution where you would actively move around the room, something I suppose is not that practical. On PC, VR could nonetheless be a very nice way of experiencing simulation games. Still, given the uncertainty regarding the movement options, the final resolution and refresh rate (I think they said 90 Hz), price factor and - most importantly - the list of games that would support the device in the first place; I feel like it's too early to say how this device will turn out.