hz refers to the tv's refresh rate which really only matters alot with lcd displays due to the way that particular technology works. DLP tvs for instance can run perfectly @ 60 hz, while a lcd engine @ 60 hz can have ghosting issues. LCDs need a higher refresh rate to eliminate the possibility of ghosting, and unfortunately that equates to more dollars.
the manufacturers have used numbers like crazy refresh rates and contrast ratios that confuse buyers and help keep prices at a premium. contrast ratios are a joke. 1 kajillion : 1 contrast can be gotten by using the manufacturers own math because there isnt an enforced industry standard and the consumer thinks its better when it isnt any different than the 10k :1 gotten using a different math.
love my Samsung 50" led engine dlp btw. if your not hell bent on hanging the damned tv like a picture frame, you can get a really large tv with great options at a much more reasonable price with a dlp than an lcd. though large lcds have come down a lot since I bought my dlp.
