No matter how popular Blue-Ray becomes, I hope to God DVDs never get put out of business at least not for another decade. I mean think about how long VHS last.
Blu ray disc movies are much better in picture quality than the dvd movies. I have stopped buying dvd movies for well over 4 years now. Sooner or later dvd will disappear like the VHS and Laser Disc. Hope this will help you out.
If your watching videos, let us say, 32 inch and smaller, The picture quality between the two is not much significant. But if your viewing it on a high-definition 50 inch TV or a 100 inch HD home theater projector, then, YES, the picture quality is so obvious.
You hope to God? Well, first of all, there is no God. Secondly, if there were, do you think He would care about Blu-ray vs. DVD? Thirdly, Blu-ray is spelled "Blu-ray" with that exact capitalization and spelling. Fourthly, DVD is over already, whether you realize it or not. Blu-ray players and discs are so far superior, it's like DVD versus VHS.
You will be able to play your DVD's on a new bluray player so you do not have to discard them just yet even if you upgrade to bluray. It is my understanding that the equipment required to manufacturer the bluray disc is different than the equipment used to manufacturer regular DVD so if that is true, manufacturers will want to phase out DVD as soon as possible so they do not have to run two separate manufacturing lines.
Personally I like seeing my equipment become obsolete. If we had not seen VHS become obsolete we would still be watching VHS. I can't even imagine how horrible that would look on my 144" projection screen. I know it would look so bad that my home theatre would have never happened. It's only through technological advancement that I have my home theatre. It simply would not have been practical with VHS and the projectors of 10 ~ 15 years ago. The obsolescence of today's equipment is the wonder and amazement of tomorrow's entertainment. I welcome it!