It may be questionable whether one can actually perceive the difference between a 720p and 1080p display at typical TV viewing distances, according to Audioholics.

Most people are familiar with the concept of 20/20 vision. However, this is a relative scale. In terms of absolute acuity, the human eye is rated at about 2 arc minutes of resolution. The natural question to ask, then, given a High Definition TV with a given screen size and pixel spacing, how does that spacing relate to the average human eye's acuity?

Consider a 50 inch (1.27 m) HDTV plasma display viewed from 8 feet (about 2.4 m). This is close to the 30 degree viewing angle typically prescribed. With a standard 720p resolution, each pixel is about 0.03 inch in size. However, the smallest spacing the human eye could separate at that distance is about 0.065 inch, according to the math in the article.

"Put bluntly, from 8 feet away while watching a 50 inch plasma TV, the human eye is generally incapable of reliably distinguishing any detail finer than that shown on a true 720p display!" Joseph Cornwall wrote.

There are some caveats, however. "Of course there are other factors that affect perceived image quality," the author concluded. "The way color is handled, the latency of pixel illumination, motion artifacts and the effects of the algorithms that fit the image data to the native resolution of the display (and more importantly the SOURCE) all play a part in a qualitative assessment of the image. It's safe to say, however, that increasing resolution and image refresh rate alone are not enough to provide a startlingly better viewing experience in a typical flat panel or rear projection residential installation."

What a 1080p system does do is allow one to sit closer, or alternatively opt for a larger screen. Both are attractive options in the era of HDTV.