There's certainly a time and a place for playing with yourself, but as a general rule of thumb it's always more fun to play with somebody else - or multiple people, if you're feeling particularly adventurous. We've all had a bash at some co-op gaming in the past, but here's a shiny, updated list of our Top 10 Co-Op Games of all Time.
It might not have Master Chief, but Halo: Reach has a place for almost all of your mates. You can play the campaign (with the all-important scoring, so you can prove you're better than your supposed chums), multiplayer, and ODST's returning Firefight mode - now with more options than ever. If you're looking for something more creative, you can even tool around in Forge mode and make custom levels and game modes. Microsoft is also releasing updated versions of classic maps for Reach as part of the upcoming Halo: Combat Evolved Anniversary, so there's plenty of life left in the game.
Gears of War 3
Gears of War 2 really popularised the co-operative wave-based survival mode with Horde, so it's no surprise to see it back in Gears of War 3 and as brilliant as ever. New features include Beast mode, which allows you to finally play as the Locust, and (finally) a four-player co-op campaign. There's also a new 'Arcade' mode which includes user-definable mutators and score tracking, so you can bring a little bit of competition to your campaign cooperation. As far as third-person shooters go, they really don't get much better than Gears of War 3.
Portal 2 might have an incredible single-player campaign, but it's also got a lengthy (and entirely separate) co-op campaign for two players. You play as either Atlas or P-Body and rummage around various Aperture Science laboratories, completing increasingly devious puzzles in each one, in order to assist demented computer AI GLaDOS. Most co-op games test your trigger finger, but Portal 2 will make you and a friend flex the gray matter.
Released in 2008, four-player side-scrolling beat-em-up Castle Crashers has become one of Xbox LIVE Arcade's most successful games. And rightly so! Set in a humorous medieval universe, your gang of valiant, primary-coloured knights go on a quest to rescue a gaggle of princesses. It's just the right mix of action and RPG elements, with your characters levelling up the more you play. With four players around one television and a copy of Castle Crashers it's far too easy to burn through an entire evening.
Call of Duty: Black Ops
There's no campaign co-op in Call of Duty, and it wouldn't surprise us if there never was, but Black Ops carves a space on the list with its four-player Zombies mode. Despite plenty of fiddly mechanics and a multitude of map-specific features, Zombies has become enormously popular - its dense layouts and complicated maps must be hitting the right chord. The mode has been so successful Activision even released a Zombies-only DLC pack last month.
New Super Mario Bros Wii
Despite making the game inexplicably harder, co-op in New Super Mario Bros is an absolute joy to play if you've got three mates round. Players three and four get the short straw (they have to play as unnamed toads as opposed to player one and two's Mario and Luigi) but for the most part it's an absolutely fantastic rendition of classic Mario gameplay with additional four-player support.
Just Dance 2
Because it doesn't all have to be about playing games sitting down, does it? Get up and have a dance about, why don't you? Just Dance 2 has some incredible cheese classics (Blondie - Call Me is my personal favourite, though it's also hard to turn down some Boney M) and some of the most wonderful and ridiculous dance moves. Playing with a second player, if you can muster up enough courage, is also brilliant - the game has plenty of dance moves for the pair of you.
Borderlands, a delightful mix of loot-grinding and FPS, is one of the definitive co-op games of our generation - and it has been since its launch in 2009. The game is so entertaining we'll even forgive it its lazy ending and disappointing Mad Moxxi DLC, and by now you can easily pick up the Game of the Year edition for pennies. We imagine the only thing that will knock Borderlands off the list is Borderlands 2.
You'll need some iron-like fingers and a brain that can fire on all cylinders, but StarCraft II is one of the most rewarding RTS games we've ever played. While most of the meat will come from you and a buddy training yourself for some Diamond league 2v2 action, there's also a serviceable co-op campaign that will happily teach you the basics of this demanding but rewarding strategy game.
To say LittleBigPlanet 2 is just more of the same would be unfair - it adds new content as well as fixing many of our criticisms of the original game. The creation tools are easier to use and more capable, the quality of levels produced by the community is far superior, and there's even more impetus for four players to mess about. What's not to like?