The TV vs. monitor thing has alot to do with size which is being left out here often, on my 46" I wouldn't sit close enough that the fuzzy edges @1920x1080 matter, my 22" tv connected through VGA looks as good as my 24" monitor and keeps me from being tethered to my desk so I'm biased by convienence too.

There's also the matter of connection type, HDMI isn't the "best" for PC displays but most newer TVs have support for more than just AV/S-Vid/Composite, with VGA/Display Port/DVI/HDMI being almost universal you can find TVs that support resolutions higher than 1080p and cables that make them look as good. It just costs more.