Most of what I'm interested in (TV wise) either won't benefit, since it wasn;t recorded on film or in high-definition. And even the stuff that was, only made it onto disc because the huge number of DVD owners made niche products worth releasing, hence it won't get a release until Blu is at least as mass market as DVD is - which will be years away - and, most likely, won;t get released at all since Blu demands much more extensive restoration and of course a hi-def transfer. Otherwise, you don;t really get an improvement, indeed, stuff can appear worse because Blu shows it up "warts and all"
I, for one, am willing to wait for quality work. Not forever, but until "niche" product is economically sustainable and the studios are willing to put in some actual work into it.