Having Started Assssins Creed II, I realize there are a few things you must apparently have to work at UbiSoft.
1) A love for Parkour. I distinctly remember thinking This guy can climb in the first AC, now this time I'm thinking he's directly related to the Prince of Persia.
2)A love for slightly off the chart Historical periods. Honestly, Ubisoft loves making games set during times that you wouldn't think were great for an Action game. Ancient Persia, Jerusalem, Renaissance Italy. Great art and history here too.
3)To show off. Every Ubisoft game I remember playing really like to take it up a notch and show off something, either what their engine can do, or their beautiful graphics, etc. The list goes one.
I just wish their DRM model for PC games was a bit less restrictive, but that's why I plan on sticking with them for Console gaming!