Quake and Quake2 look just fine on my old Work laptop (Samsung GT9000, 2 1/2 years old, 1400x1050 15" screen). DVDs look just fine, too. I saw a cheap LCD TV today and the quality was just rubbish, though.
Contrast and definition are just fine, apart from when working with photo editing where very light shades don't show right, or when playing low res stuff (though it's not that bad).
On my Miggy I use a 15" Sony Trinitron CRT that looks great, but it cost £200 new - considerably more than most 15" TFTs these days ;-)