Seems like some people are missing the point a bit. It is not that you must change all your DVDs to blurays, but it is the same thing as VHS to DVD. New things will comes only on DVD, and if you want, you can buy the old movies you have on DVD. It did not make VHS's not function, they still work even today. Personally, I just couldn't go back, streched tapes, bad quality picture and sound. The more you watched it, the sooner it died. No thanks.
Even though DVD is good, and I plan to keep my DVDs for years, I'm still going to buy a bluray player when the prices come down a bit.
Funny thing about SD quality, the last ice hockey world championships were about a few months ago. The quality was so bad on SD that when the camera moved even the slightest it looked like the players weren't using sticks at all. I wathced few games on HD, and I must admit it, it rocked.