Intense Movies that Keep your Attention

I have a long flight coming up (24 hours) and I'm looking for some really good movies that will distract me and keep my attention and keep me wanting to watch.

The last time I did this, the best example was Saving Private Ryan. Second best was The Departed. I don't know why, but that long movie just kept me going the whole time.

Anyways, if anyone can think of really great ones, I'm all ears! Genre isn't nearly as important as the fact that it keeps me going.