#5: The World Ends With You (2008)
There is more innovation in The World Ends With You than in the rest of the decade of gaming put together. In every single gameplay mechanic it flies so far away from what we've seen before that it's daunting. And yet it is without misstep; from an adjustable difficulty scale directly tied to rewards, to a system wherein you both influence and are influenced by city-wide fashion, to the controversial dual-screen combat mechanics, its eccentricities are both brilliant and consummately executed. And it uses them to tell a story about individuality, teamwork, and culture that's thoroughly worth telling.
#4: Metal Gear Solid 2 (2001)
Its sequels were equally outstanding games but it's Metal Gear Solid 2 that to me had the greatest impact of the franchise. There is nothing about Metal Gear that is small in scale; like a gaming Titanic, everything is epic, historic, possessed of a gravitas that slams you in the chest at every opportunity. It's utterly unafraid to abandon its own past successes and explore new ground, it's packed with hidden detail, brilliant twists, and thrilling set-pieces, and the production values put Hollywood to shame. Metal Gear knows how good it is; the game is confident that were no one to ever play it, it would still remain one of the greatest games ever made, and that confident shines through every polygon and infuses every line of dialogue, leaving you awestruck before it.
#3: Dragon Age: Origins (2009)
XBox 360, PC, PlayStation 3
I'm still upset about the callousness of Dragon Age's ending but my outrage would not be possible had not the proceedings up to that point been so perfect. The characters who populate Dragon Age - and particularly your party companions - are the best written characters to ever appear in a video game. You care about them as real people. They are multi-faceted, never stereotypical (well, maybe Oghren), and their approval or disapproval of your actions really matters on a powerful, emotional level. And on top of that the game constantly presents choices that matter - not because of their impacts on the game (although they do, unfailingly, have impacts) - but because you're left knowing that you made that choice. Real meaning comes from within.
#2: Portal (2007)
PC, XBox 360, PlayStation 3
No one hates Portal. No one. I don't think there is anyone who was ever born who hates Portal. It's so incredibly rare for the gaming community to come together as a single voice around one game and say, "This is ours." And yet Portal manages it. It's not the portal puzzles themselves, although those are certainly decent, but something about its short, self-assured scope, its mood, its dry humour, and its now ubiquitous cake references and ending theme. We all love Portal, and absent being given a sequel truly eye-gouging in awfulness, I think we probably always will.
#1: World of Warcraft (2004)
There's no real doubt about it - this is World of Warcraft's decade. It's the game that ate a genre - for five years it's had no serious competitors in the Western MMO world, with everyone else squabbling over the meagre second place scraps. It's conquered gaming culture, it's enervated the mainstream, it's inculcated, launched, and raked in the profits of a multi-media marketing empire. It's the single game responsible for the majority of the profits of Vivendi's gaming division (when such a thing still existed) and the driving force behind the merger of Blizzard and Activision into the monstrosity I like to call Blactivision. It's been parodied in print, in song, in film, and in a memorable episode of South Park, it's the worldwide face of online gaming, and as 2010 rolls around despite being five years old in an industry that punishes titles not released this month it's still trending upwards.