Resolution is only one factor - contrast ratio and proper black levels, not to mention a proper calibrated display, are all just as important. Your seating distance also determines how well you can discern detail between a 720p and 1080p display.
FYI the term 'HD ready' is used to describe a TV that displays HD resolution but does not have a built-in ATSC tuner i.e. it doesn't have anything to do with display resolution.