The difference is there yes and I can see it. But since the difference doesn't blow my mind (A.k.a SDTV are just fine) I consider it to be negligible.
But that might just be because I almost never use my TV, and when I do use it it's to play games that appear just fine on a SDTV (Ps2, Wii, other older gen consoles). I rarely play on my 360 and PS3 which are nowadays just used to watch videoclips and listen to music.
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http://www.youtube.com/watch?v=6Lo0qD6rOz8