The first game I ever played was (I think) either Secrets Weapons Over Normandy on the PS2, Assassin's Creed 2 on my friend's computer, or Need for Speed Most Wanted, which was also on my friend's computer. All amazing games.
I want to see how in depth customization goes, as in how many ways you can design your character to fit your playstyle. I'm personally an assassin type guy, so I'm also looking forward to infiltrating areas quietly like in Deus Ex.