I have this issue. Approx once every 3 months or so, the TV will exhibit this behavior. I just unplug the power and all the HDMI cables and leave it overnight. The next morning, I plug everything back in and it works again.
At least there is a work-around. Yes, it is annoying, but the only time it interrupts me is if I am wanting to watch something that evening. I just ran some composite cables from the satelite receiver to the TV. SD only, but for that one night every 3 months, if I want to watch, it works.
I thought Samsung would have fixed this by now with a new firmware, but I guess not.