Sweet deal. I'd recommend Civ V over Mafia II, unless you're unusually opposed to strategy games. Civ V is very easy to get in to and--once you're hooked--very hard to get out of. It's the ultimate, easily graspable "just one more turn..." game.
Mafia II is still one of my favorite games of its generation, though.
Mafia II is still one of my favorite games of its generation, though.