There is currently a new game in development by the Prince of Persia crew that is really impressing me. It is called
Assassin's Creed and offers some nice innovations.
The story takes place in the Middle East during the Third Crusade and puts you in the role of an assassin. One really cool thing is that you have complete freedom. The team has reconstructed several famous cities like Damascus and Jerusalem that you can explore. An innovative input system helps you to climb up on every building that has some grip.
But the best of all next to the great graphics is the crowd simulation. The developers have put much effort in making the world vivid and believable. When moving through the streets you can push away people who are in your way which appears as an impressive interaction. You can even use the crowd for hiding when approaching to your victim, what is called "social stealth". This is a really cool feature and as far as I know, it is the first time that a commercial game uses crowds as a gameplay element.
For more information on the game and some nice videos see the following site:
http://pc.ign.com/objects/839/839699.html