Its like the difference between the telegraph and the telephone.
Nobody thinks they care about the difference between Blu-Ray and DVD, until the first time you see Star Trek, or Iron Man, and realize you have never really seen a picture before.
You won't want to ever go to a theater again either.
Of course one of the big dogs at Sony said he couldn’t tell the difference between a good upconverter of regular DVD and Blu-Ray until the TV got bigger than 50 inches. Even non-upconverted doesn’t show much difference at under about 35.