There are several different methods of measuring contrast ratio, just as there are several different methods of measuring wattage output on audio equipment.
The 2 most common methods of measuring contrast ratio are "native" and "dynamic". LCD mfgs. all advertised "native" contrast ratio up until a couple of years ago. At that time (2005 or so) an 800:1 contrast ratio was pretty common on sets from the better mfgs--Sharp, Samsung, etc, while 400:1 or 600:1 was average for cheaper sets.
Then Samsung started advertising 2000:1 or 3000:1 contrast ratios on sets whose apparent ability to reproduce black was no better than competitors advertising 800:1, but the word "dyamic" preceded the number. Pretty soon it was revealed that Sammy had found a different way to measure contrast ratio that gave them a much higher number to advertise and thus impress potential buyers that were unaware of the chicanery they were indulging in.
Pretty soon all the other LCD mfgs started to use the Dynamic figure in self-defense, though Sharp is at least honest enough to also list the "native" contrast ratio. The Sharp 42" D62 series 1080p lcd has a dynamic contrast ratio of 6000:1, while the native contrast ratio is listed a 1200:1.
Sony, afaik, does not advertise contrast ratio for it's sxrd sets. Contrast ratio has been measured at at least 10,000:1 by several independent testers using the most conservative method of measurement, not the "dynamic" method.
The Samsung you mention is a dlp rear projection, not an lcd, as BillP says. I am surprised that using the "dynamic" figure the contrast ratio is as low as 10,000:1. Perhaps their variable iris is still not adjustable in order to force the blindingly bright image neede to impress J6P in the showroom and sacrifices contrast ratio in real world situations.
That being said, 10,000:1 Dynamic is comparatively a pretty good number and should show good blacks and shadow detail in all but a completely dark room, and even in the dark should be just fine for all but the fussiest videophile.
