If you go see the Matrix Reloaded (no link, I'm sure you know where to find it), make sure you sit through the credits and see the tease for The Matrix Revolutions. A guy at work brought up an interesting question about the movie...[Spoiler below]
Is Zion just another part of the matrix? Afterall, Neo had the power to stop the sentinels while out of the matrix. Agent Smith (shown at the end of the movie) is the anomaly in the system that the Architect cannot account for. Smith is why something different is going to happen this time around. I still have no clue what though.