HTPC, dude. It's a category of computer specifically created to be a home theater thing while not being big and loud and power-sucking like a standard desktop computer.... and even if you're buying prebuilt, they're available cheaper than the Wii U.
http://www.newegg.com/Product/Product.aspx?Item=N82E16883218010
$158, which is over $100 less than the Wii U's basic model (though it needs storage like the Wii U anyway).
http://www.newegg.com/Product/Product.aspx?Item=N82E16883103785
$225, 320GB harddrive, keyboard and mouse included.
etc.
This is one of the reasons modern devs don't have as much interest in hacking consoles as they used to. You can get an HTPC or something like it for a hundred bucks cheaper than even the base model of the Wii U, and you don't need to hack shit to get it working (unless you go Ubuntu, hardy-har).
EDIT: And of course I have to mention that softwares like WiiMC and such are most often ports of PC software in the first place, often with features cut.
But an htpc won't play wiiU games......
There is a reason why there are still consoles on the market and most people don't keep their last gen console once a new gen of consoles comes out.....