Harvey Keitel is always a win; from his Deadpan Snarker wit (i.e. how he reacted upon learning that someone wrote off the tip Ben and Riley tried to give) to his Reasonable Authority Figure personality in both movies, he makes the films transcend their "heist movie" premises to become somewhat pseudo-educational and patriotic.
Sadusky: Someone's got to go to prison, Ben.
Ben and Riley's scheme to snatch the Declaration was amazing.
Of particular mention are the scrolls from the Library of Alexandria. No matter what they contain, recovering something from the ancient world long thought lost and considered worthy of being kept in a great library would be an utter coup for archaeology, anthropology, and history.
Riley gets one in the sequel when the knowledge he has painstakingly researched in his The Templar Treasure in regards to the President's secret book is proven to be accurate. It's an even better CMOA for him than his surprise revelation in the first about the daylight savings not existing back in the 1700s.
Riley taking Ben and Abigail all the way through Buckingham Palace and causing them to "fight" so they restart their relationship again.