Why are some flat-panel TVs so much less expensive than others? It's a common misconception that all plasma and LCD flat-panel TVs are HDTV-capable by definition. This is not the case, at least not in terms of display resolution. While the vast majority of flat-panel sets are what we at Best Buy call "digital TVs" (i.e., capable of progressive-scan display), they can be divided into two distinct classes of resolution: EDTV (Enhanced-Definition Television) and HDTV (High-Definition Television). With very few exceptions, both classes are capable of displaying signals transmitted in any of the 18 accepted ATSC digital-TV broadcast formats; the critical difference lies in HDTV's superior capacity to render the highest-quality signals at full resolution. EDTVs (and ED-ready TVs, also known as EDTV monitors) must only be able to reproduce a minimum of 480 progressively scanned horizontal lines (480p). This makes them ideal for displaying DVD content, which is limited to 480p output resolution by definition. Almost without exception, EDTV tuners (whether built-in or stand-alone) are equipped with video scaling circuits that downconvert higher-resolution broadcast signals to the maximum resolution of the display device. Thus, an EDTV can receive and interpret true HDTV signals, but must display them on-screen at a somewhat diluted resolution. If you want the best picture TV has to offer — now and well into the future — EDTV won't take you all the way there. You'll want to seriously consider the cream of the TV crop: HDTVs (and HD-ready TVs, also known as HDTV monitors) incorporate display electronics that are capable of rendering a picture comprising at least 720 progressively scanned horizontal lines or 1080 interlaced horizontal lines. These numbers correspond directly to the highest-resolution formats defined in the DTV standard (720p and 1080i, respectively), so true HDTV displays can reproduce one or both of these signals in what's known in industry parlance as "native resolution" (most render either 720p or 1080i in native resolution, and convert the other high-definition format to their native resolution — 720p to 1080i or vice versa). HDTVs and HD-ready TVs must also be able to render a widescreen (16:9 aspect-ratio) signal with a minimum display resolution of 540 progressively scanned or 810 interlaced horizontal lines. This specification typically applies to 4:3 HD-ready TVs, and ensures that widescreen content displayed on these sets meets minimum standards of resolution to be considered truly high-definition. The bottom line: EDTV presents a lower-cost alternative to true high-definition display resolution, but there is a noticeable difference. As HD-quality programming claims the airwaves, sooner or later you'll want a TV that can deliver it in all its glory. Only a true HDTV display can deliver on that promise.