Blu-Ray will not be as popular as DVD for a couple reasons.
First of all, there are no significant differences in features between Blu-Ray and DVD. The jump from VHS to DVD added chapter selection and skipping, audio commentary and special features, decreased physical space, the elimination of rewinding for a couple minutes to get to the beginning of a movie, and increased durability. It also offered increased picture and sound quality. Blu-Ray adds... increased picture and sound quality and that's about it.
Second, 90% of consumers are not going to be able to see much difference between a Blu-Ray movie and an upscaled DVD, and half of those who can won't care, and half of those who DO care will care more about the price difference between DVD and Blu-Ray players and movies.
Also, don't look for HDTV adoption rates to jump very much with the end of the analog broadcast signals in the U.S. Those little converter boxes are SUPER popular. Why pay hundreds for a new TV when you can just pay 20 bucks (after the government discount) for a converter box?