According to my Daily Mail, this morning (The article doesn't appear to be on their website): "Why your HDTV may only be half as clear as you think" ; HD broadcasts offer up to two million pixels, but 99% of TV's being sold as "HD Ready" have only 921,600 pixels (44%); Only one set on the market, the: Philips 37PF9830, meets the full spec.
"Dixons insisted that most consumers would not be able to tell the difference between images on a 720-line and a 1280 line sets(sic): 'Our technical experts would defy anyone to see a difference in the clarity' said a spokesman, It would be, however, on a new generation of huge 65" TV's about to become available".

Aware people like Empeggers will note two things:

1) Marketing hype is marketing hype and relies on not giving you reliable, unequivocal information.

2) Whatever the metrication fanatics and Neil Kinnock think, far from needing to spend millions on Km. road signs, before the Olympics, we shall all still be watching them on sets measured in inches!