What are your favorite songs composed specifically for a game?

Mine are the http://www.youtube.com/watch?v=FIYUgo2FKuo

http://www.youtube.com/watch?v=Gs2axjnJUbMfrom Assassin's Creed 2

http://www.youtube.com/watch?v=qfFvOt5GPr8, also from Assassin's Creed 2.

http://www.youtube.com/watch?v=ZWuNf4gxwuM

And of course, http://www.youtube.com/watch?v=h_s9Jb5AWXU&feature=player_embedded