Sure, Youtube would be the first app no doubt about it, I'd like to see Casey Neistat on TV every night, but now imagine instagram, snapchat, twitter, facebook and all social apps on your TV. Phones will still be widely used on the go, but once people get home they get splatted on the couch and TV would become the main screen from where to enjoy all possible entertainment.

I personally was thinking as a developer, I'd like to code on my TV, I'm sick of the desktop and the laptop, my eyes and back are suffering the most. I need a comfortable chair LazyBoy-style ten feet away from the screen with a wireless keyboard and trackpad which can be used as remote, that's it, nothing else. So for me it would be Xcode and Sublime on my TV, HN and Reddit, and the possibility to develop a million apps just like your iPhone/Android. One single box, the size of a soap bar, attached to your TV, and let developers make it the new platform. Desktops and laptops would be the first casualties (except for enterprises). That's my vision.

Never underestimate the imagination of a million developers with new and shiny toys. TV is the next wave.