A few that have been recommended already which i totally agree with:
Casino Royale
Pans Labyrinth
No Country for Old Men
Wall.E - which is probably the best looking BluRay in my collection.
On that note, all of the Pixar releases are stunning. They go above and beyond with extras, and the transfers to BluRay are the best in the industry (It helps that the original source is digital, but they are superior to the likes of Dreamworks animation); Wall.E, Monsters Inc., Ratatouille and Cars are currently out on BD.