Contrast ratio: An HDTV's contrast-ratio rating is supposed to measure the difference between a TV's darkest blacks and brightest whites--the idea being that we find images with a high visual contrast more realistic. Unfortunately, since manufacturers self-report contrast ratios without any standardized testing guidelines, contrast ratios aren't a reliable indicator of a TV's picture quality in the slightest. Related:
Response time: Response time measures the time it takes for a pixel in an LCD to turn from one color to another--either from black to white to black again, or from one shade of gray to another shade of gray. This spec is useful for making sure you have a monitor without a "smearing" or "blurring" effect around moving objects.
However, unless you look at the fine print, it isn't always clear which measurement the manufacturer reports (the black-white-black transition takes about twice as long as the grey-grey transition), and these days, response times are generally good enough that most people don't need to worry about them. Related:
Refresh rate: The difference in image quality between a 60Hz LCD HDTV and a 120Hz LCD HDTV is tremendous; after 120Hz, though, refresh rate is really not so important. We've seen 120Hz TVs beat 240Hz TVs in our motion tests, because the 240Hz frame-interpolation algorithms create "judder" artifacts. Related:
Size: This is a big deal, but not necessarily in the way you think. Most people want the biggest TV they can get for their buck. However, if your living room isn't large enough to support a lot of space between your set and your couch, you might end up with an inferior-looking image overall. Your mom was right: You don't want to sit too close to your TV. With a bigger set, you'll be able to see the individual lines in the TV image. It's just like sitting in the front-row seats at a movie theater. Related: