I really think the Blockbuster app is going to a complete failure. There is no way I'm going to pay $4 to rent a movie that I can ONLY watch on my 4.3" display, esp when there is a perfectly good HDMI port available that should be taken advantage of. I realize they aren't using the HDMI due to some sort of contract limitations, which in my mind is irrelevant, I'm still not going to pay the $$ for such limited usability.
I don't know how the Netflix mobile app will work, but I believe the Netflix online service I use on my Blu-Ray player lets me watch as many movies as I want as part of my $19.99/month subscription, AND watch them on my 55" HDTV. I hope they do the same on mobile devices.