Favorite Xbox Game

This is a tough one for me as I have spent a lot of time playing a lot of games which I really did enjoy but if I go back to the days when I used to joint own an old clan I had we used to play Halo 3 and Rainbow Six Vegas 2 a lot (9 months straight for Vegas 2) and they were a lot of fun and gave us many gaming memories. If I had to choose any favourite game on the Xbox it would have to be those two just because of the fun and memories we made.