Unless you have a high definition tv you wont see any difference while watching a blu-ray dvd.
We have a HDTV and a sony blu-ray dvd player. There is a HUGE difference. Blu-ray produces crisp, beautiful, lifelike scenes. its almost like looking out a window it looks so real.
If your watching regular tv broadcast in HD theres an obviously clearer, crisper picture too, again as long as you have an HDTV.
If youre not seeing the obvious difference then you either have a older non HDTV, or your eye dr lied to you.