It's not blue ray DVD for a start.... it's just blue ray.
HD ready means a TV has a HD screen but no inbuilt tuner capable of HD so it requires it to be connected to an external HD source, such as a blue ray player.
You also have to consider the picture quality of the blu-ray disc's themselves - I've bought about 50 films in the 6 months since I bought a player and with quite a lot of them you do wonder if they really did re-master them for blu-ray. But for others e.g. The Dark Knight and I just watched The Tree Of Life at the weekend, the picture quality is superb.