I'll kick it off.
I don't want to start on an acrimonious note, but I'm gonna nominate Far Cry 2
as my first game. I thought it was great, and I'd love to see more from designer Clint Hocking. What are the chances he's working on HL3 at Valve?
I loved this, mainly for the 'immersion'. The intro cutscene, a seamless journey from the airport into the heart of darkness, was just lovely. I loved it when you pulled up your map, or ripped a bullet out of your thigh with a pair of pliers. I liked the horrible bastards who were your buddies, and I liked the freedom to approach missions as you saw fit. The driving and boating was fantastic. The shooting was solid, and that little bastard in the boat with the mortar was infuriating.
I'm giving it a 9
What about you folks, got a game to share?