Sony has its own version of HD, called Blu-Ray. The New York Post reports that the reason Sony acquired the MGM movie library, was so that they could flood the market with their Blu-Ray formatted titles, essentially forcing everyone else to adopt their HD standard. They want you to replace your entire library of DVDs with Sony-formatted versions of the same thing, only "high definition".
"Most people are not eager to upgrade all over again", says Bill Hunt, editor of The Digital Bits newsletter.Duh. Rent, don't buy. Don't let them milk you.