If you're shopping for an HDTV, is it worth it to pay more money for a set that supports higher resolution (at the same screen size)?
The latest digital TVs support different maximum resolutions: 480p (853×480), 720p (1280×720), & 1080p (1920×1080). The first resolution (480p) is typically referred to has "enhanced definition", while the last two (720 & 1080) are referred to as "high definition" (HDTV).
Digital TVs will down-convert higher resolution signals to the resolution that the TVs support. So a 480 set can still display a 1080 signal by down-converting the signal to display fewer pixels.
For the same screen size, higher resolution sets cost more money. Most people would assume that for a given screen size (say 40 inches), a 1080p set would be better than a 720p set. But depending on how far away you are sitting from the screen, you may not be able to see the difference in quality because the pixels will be too small. In that case you're wasting your money. So at what point are you wasting your money on pixels you won't be able to see?
Carlton Bale blogged on this question, and created a chart (see below). For a 40 inch TV, and sitting 8 feet away, most people will see the benefit of 720p over 480p. But most people will not see any additional benefit going to 1080p. So if you're buying a 40 inch TV and watching from 8 feet, it's a waste of money to pay more for a 1080p set.