The Chromecast/ NOWTV dongles use a HDMI port on your TV. These and Generic 'PC on a stick' dongles allow just about any internet content to be displayed on the TV. The generic dongles also allow the addition of an external HDD plus keyboards and so on (Dont know about Chromecast/ AirTV etc).
Our internet has just moved into watchable speeds and have been watching HD films via Netflix on our 'smart' TV and its perfect, no adverts, no buffering. The TV itself can stream to other devices. It can even record if something is connected to the USB port.
The Sony I have has loads of TV apps built in with the opportunity to add more. It also streams Microsoft based stuff from my main PC and the Mrs' laptop. But not apple stuff so no iTunes - yet.
I watched Road House for the first time ever, and in high definition. Mrs LGF was concentrating very carefully on Patrick Swayze for some reason...