Valve has recently started to accept pre-orders for its Steam Hardware offering. This means that the Steam Controller and the Steam Link are now available for pre-purchase. Both of them are priced at about 50 USD, and if you purchase both you could expect to be able to play your PC games on the couch and without the need of a mouse and keyboard - as shown in Valve’s promotion video:
Last time I had the Steam Controller in my hands I was not extremely convinced by the appropriateness of the haptic pads on each side (see my earlier post on the subject), but time will tell.
The Steam Link itself is an ARM-based (ARM7 class with dedicated h264 decoding chip) device with a custom Linux kernel (as revealed by Valve a couple of days back). On top of that there will some additional Valve software (probably a kind of Steam client, at least for login to the service). So it’s technically going to be the first Steam ARM client running on top of an Linux ARM stack (i.e. not Android). It will be used to stream games from one host computer running Steam (whether Windows, Mac or Linux) to your TV. As you can expect, the device is going to be locked down and will not allow any custom firmware or modding, for easier approval by regulatory agencies.
While it does not rely only on a wired connection, it is strongly recommended to use one, and as much as possible a Gigabit-level connection. In case you have never tried in-home streaming, you should know that it works quite well if your connection is reliable, and there’s less lag that you might think in the first place. It remains to be seen if this Steam Link device can do the job as well as a dedicated computer, but there’s no reason it should not - even a Raspberry Pi 2 should be powerful enough to do the job. Note that Valve has not announced whether or not the said modified Linux kernel will be made available for other devices or not (it should in theory since Linux is GPL’ed).
Valve has just announced as well (according to PC Gamer) that 35% of their custom hardware has already been sold, so if you want to be first served as soon as October, you may want to order your Steam Controller and/or Steam Link soon (if you are in a location where it’s possible to order them: Australia and Japan seem to be out as far as I can tell).