hard to say, it is not an exact science. Smaller (international) studios that are not releasing on HD are the ones I am more interested. The large Hollywood studios I go with the assumption that they will re-release in HD. The larger the studio the more important the movie the bigger the chance that there will be a re-release. So for example when Maurice Richard came out, I ran out and bought it, maybe one day it will be available on BD, but it was a movie I wanted and am not willing to risk that it won't. I have been caught in the past waiting a bit too much to buy the local movie's DVD. On the other hand I did not buy Cars even though it is a movie I want, I think there is a god chance that Disney will sooner or later put it on BD.