9 | Halo: Reach | Xbox 360
Changing the Halo formula again, Reach improves on the spectacular Halo 3 with new gameplay elements such as armor abilities, new melee attacks, and equipment power-ups. Taking the fight online also shows a highly refined multiplayer system that adds new modes, like Firefight, and an updated Forge mode. Not only can you destroy friends and foes with the best of them, but you can also craft memorable levels to boot.
8 | Borderlands | PC, Xbox 360, PS3
A blend of first-person shooter and loot-driven RPG, Borderlands is one of the most fun games available on PC. Your goal is simple: survive as you seek out “The Vault,” a place that contains fabulous alien treasure and technology. But the planet of Pandora is a dangerous place, full of nasty monsters and psycho convicts. The game gives you plenty of weapons -- developer Gearbox Software boasts that they have more than 1 million firearms in the game -- and each of the four characters have special skills suited to their roles, like sniper and tank.
Exploring the world of Pandora, either on foot or in weapon-baring buggies, is just fun; the gunplay is fast, and online co-op with up to four players is smooth (not to mention the best way to play the game). The game has four pieces of DLC—if you don’t purchase the Game of the Year Edition, which has all of the DLC, check out The Zombie Isle of Dr. Ned and The Secret Armory of General Knoxx.
7 | Left 4 Dead 2 | PC, Xbox 360, Mac
The team-based survival horror multiplayer game was pretty much invented by Valve when they released Left 4 Dead. The premise of both games is simple: You and three of your friends must fight your way through hordes of zombies towards a safehouse or extraction point. But if you stray too far from your friends, you might be picked off by a “hunter” zombie or strangled by a “smoker” zombie. There are few games out there that make you rely as heavily on your teammates, or are as genuinely frightening.
With the sequel, you get a new set of locations in the Deep South, a new cast of characters, and the addition of melee weapons. Like all of Valve’s games, Left 4 Dead 2 is best played on the PC. The DLC packs are all free for PC users and help flush out more of the story and the overlap between the events of Left 4 Dead and the sequel.