Just to clear a few things up.
Technically anything over 720P is considered High Definition, and any TV of this resolution or higher can call itself a HD TV.
HD ready and Full HD are in reality marketing constructs.
Marketing people needed a way to differentiate their various models (or a way to fool people into thinking that their 1080P TV was more desirable than a competitors 720 model, even if its image quality sucked) from one another.
In the big scheme of things (and I can see the flames igniting) Resolution is not the most important aspect and never will be.
Colour quality , contrast and even response time are more important.
This is true in other areas too.
The photography boffins here will tell you that it doesn't matter how many megapixels your camera is, if you have a rubbish lens you will get rubbish pictures.