DVD players that convert standerd def dvd's to hd work alright, but it really depends on the movie
There are also hd dvd players which are what the name implies
I think there is a blue ray dvd player out there that can also play regular dvd's
My honest opinion is that blue ray, well any dvd's, are a waste of money. You can just rent the movie. But if you must have it on hard copy, I say just stick with hd dvd's