Advertisement: Savvy flat-panel shoppers have added a new acronym to their lexicon: LED. It stands for "light-emitting diode," and represents a revolutionary breakthrough in HDTV picture quality. LED TVs are alone in their ability to deliver the deep, inky blacks that give an HDTV realistic image contrast and natural, vibrant colors. But for all the buzz, not all LED TVs are the same. That's why industry innovator Toshiba went the extra mile to create the ultimate HDTV, the new 55- and 46-inch REGZA SV670 Cinema Series.