In my current experience HDMI cable also play important role. I got a cheap one and picture on tv is overscanned, meaning it doesn't fit on screen and edges all around are out of frame, losing about 40 pixels on each side. Changed cable and viola everything is fine.
Another issue I have is that I connect PC to a home theater for 5.1 sound, (TV plugged in to it too) and the problem with this setup is that I must turn on the home theater receiver before I turn on PC, otherwise PC would not recognize it and it will have to be restarted. But I'm pretty sure it's the receiver issue, connecting directly to TV works fine.
As of mentioned pixel size issue, unless you are using it as monitor and sitting 4' away from it it's crystal clear and perfectly readable from a couch.