The natural spiritual successor to the Sim City franchise, Cities: Skylines is everything the last Sim City should have been, and more. I'm in awe of how beautiful this game is graphically, and how new user friendly it is gameplay-wise without being dumbed down. Buy this game, and then copies for your friends, your relatives, and even your in-laws. Actually, forget that last part. You don't want your in-laws to enjoy themselves. Get them the latest Sim City.

Edit: Keeps getting better and better with every addition.

Edit 2: Years later I still love this game and still highly recommend it. It does still have stability issues when you throw mods into the mix, but as long as you don't go overboard it should be manageable.