I'm currently looking for scenes when I can compare effects of HDR. I have couple of films on BR in 2 versions - one in HDR, second in SDR. My heuristic is to look 2 kinds of scene:
very bright scene in background, and in very first plan I can see and object - e.g. looking through window during sunny day, with a large object in very first plan
very dark scene with a couple of small bright points - e.g. street at night with street lights
I think that all, but maybe you have better idea?
In other words, how find good scenes where HDR results are easy to detect?