If it was me I'd take the cheap route if all you really want is to watch TV/Movies now and again my cheap solution would be a raspberry pi with openelec (XBMC) installed as the OS.
But of course that assumes you either attach a drive of some sort (would probably need the newest board with 4 USB connectors) or set up a NAS to share the files.
Then again theres hundreds of cheap media boxes that you might find more appealing I just like playing with the PI.
Edit: Forgot to mention you can have multiple Os's on different Micro SD cards so you could run Linux or do something like this
to play Emulators at will.