Movies with Great Sound

My work had a 5.1 surround sound setup on clearance for $160. I saw it yesterday and figured I'd give it a day to mull it over. In that day, it dropped down to $120, so I took it as a sign. I set this fucker up and it was relatively painless, and it works.

What are some movies that really shine in surround sound? Probably some action movies where the bullets fly from every direction, but anything that helps with the immersion.

Thoughts?