Pirates of the Caribbean looks great on Blu Ray. Pay attention to the ocean and background detail.. It is impressive.
There's always Rambo 4 also, there's nothing quite like a high definition massacre in full surround sound to help satisfy one's blood lust.
Anything new that doesn't rely on a lot of CGI and overly digital visual effects will be a good way to test it out. The extra-sharp picture makes digital stuff look even more digital and fake, which can ruin some scenes, I think.
Pay attention to the fake fires in Pirates of the Caribbean 1 and you'll see what I mean. Watch a scene on DVD, then the same on BR and you'll see what I mean.