The biggest difference is pixel size. TV's have bigger screens typically and are meant for sitting farther back. For example you have a 22" monitor and a 32" tv, both @ 1080p. The TV is going to have larger pixels which you may or may not notice when your eyes are like 18" back from the screen. Also input lag, the delay between the television or monitor receiving a signal and it being displayed on the screen, is typically higher on TVs.