I'll see if I have time to post some screenshots of PC games rendered at 1366x768, but displayed at 1920x1080 tomorrow (Aug 21st) or Wednesday (Aug 22nd).
You can always hook up your console to your HDTV and see for yourself. Generally, console gamers don't complain about poor graphics quality unless the graphics in the game itself truly sucks. The only difference between a HDTV and a monitor will be the size.