Starcraft II: Wings of Liberty (Mac)

I absolutely love it. This game utilizes all aspects of the real time strategy genre. If you love competitive RTS gaming then this is for you. From the bottom of the competitive ladder (bronze-silver-gold-platinum-diamond-mas​ter-grand master) you get a competitive edge no other games can provide. You're constantly find yourself trying to improve and beat the better players with any of the three races (Zerg, Terran, Protoss).
Starcraft 2 Wings of Liberty focuses on the Terran race(Humans). With your vast array of upgraded marines to insanely violent tanks and Battle cruisers you can roll right over the Zerg menace in the story line. When playing the online multiplayer you can choose to play by yourself 1v1 or you can pair up with a buddy or two and pit against the opposing team. If you are a fan of alien thriller movies then you should probably pick Zerg were your goal is to over throw the opponent with mass quantities of units such as the zerlging(a rather fast insect like ground unit) or the Ultralisk(reminds me of a giant beetle with 4 legs and 2 arms that act as a buzz saws).If you are a very analytic person i recommend Terran. Terran focuses on the time of the engagement and the positioning, so its all about placing those tanks in just the right spot. If you think placing any unit anywhere on the map at a whim then Protoss is for you. Protoss is a very mechanical race that sort of remind you of "War of the Worlds" creatures. Starcraft 2 also has a professional gaming scene with over 20 teams in the world competing for major titles like GSL or NASL, so if you're into
e-sports then this is also another bonus.
RTS fans all over have played starcraft 2 and if you havent yet i HIGHLY recommend you do.