I am personally not a huge fan of streaming, I'd prefer to just pay a decent price per movie (not $30 like Blurays) and get a nice HD file with no DRM, no ads, and freedom to do whatever I want with the file (like iTunes music I guess? Though I don't even want to use that service... I prefer to just find songs on Youtube now... convenience I guess).
Convenience really is my big issue; Steam has proven it's true for others too. It's much quicker to get a movie via tpb or where ever, than to go hunting around the few remaining video stores or try to find any legit place online (especially if it's a foreign film or an obscure 70's one).
The other annoying thing is Youtube take-downs. There have been so many times where I wanted to show a clip of some show/movie to a friend and then couldn't find it on Youtube anymore :(.