WiiU gets the most play followed by my early steambox build. The steambox that will be released has just shy of two hundred games ported so far and only valve AAA games like LFD2. I will probably get a steambox for the living room to compliment the WiiU probably a mid range one with a GTX 660 or 670. Until AMD improves their drivers for the steambox I am not considering them. The steambox is basically just an Ubuntu 12.04 linux box with valve logos and big picture mode... I use 13.04 due to significant updates to kernel and graphics stack.
I think this is my combo for this gen. The PS4 is OK but won't compare to a GTX660 or 670 powered steambox (why use a 680 or titan when the end goal is 1080p?) and the games are cheaper on steam. I don't like all the XBOX taxes (pay MS so I can use my internet connection... no thanks) so I won't consider the 720 although I will check it out to see what improvements they made to kinect (hopefully a lot).
And I hate retail games, I hate shopping for them, I hate having to swap out disks. So much so that I even skipped ME33 for the WiiU because I would have to go buy the disk. I am download only from this gen on.