The introduction of the Steam Box not only blurs the line between console and computer but will bridge the two. Essentially a computer that's dressed like a console. Steam could make a huge splash in the living room gaming market with the right moves and really change the landscape of couch potato gaming.
With all these options that are not very different at all, I think the choice to the consumer will now be more about brands choice, the ecosystem where your friends play, and the platform that offers you the most features that you want.
For more in depth reading and the inspiration for this article go to PCWorld: "What the 'console-ification' of PCs means for gamers".