Freelancer (PC) - A lot of people might not have heard about this game, but it was a game that was hyped up at E3 and then slipped under the radar after it's release in 2003. A lot of reviewers complained that due to do the takeover by Microsoft of developer Digital Anvil, a lot of ambitious features, like a persistent universe, ended up being cut. Despite this, I still love this game. I spent countless hours over 2003 and 2004 playing this space sim online with a small group of friends. As of this date, I can safely say that I have played Freelancer more than I have any other game on this list. A dedicated mod community increased the life of the game, with one very nice person adding in every single spacefaring vehicle from sci-fi movies and TV shows (yes, you can fly that stupid ship from Firefly). With a very cool artistic style and some of the best combat I have experienced in a space sim, Freelancer is a very worthy entry to my top 10.
Freedom Fighters (PC) - Another sleeper hit from 2003, Freedom Fighters won me over with its simple squad based combat, epic orchestral score by Jesper Kyd, stylized visuals and Red Dawn-inspired storyline. The idea that your actions in a different mission could affect what you were doing at the moment was something that appealed to the strategic side of my brain, and setting up traps for the dirty Commies with my squad was always fun. Even as a lifelong Canadian, I couldn't help but shout "AMERICA!" when the main character, Chris Stone, lowers the Soviet flag from atop a landmark and raises the Stars and Stripes.
Uncharted 2 (PS3) - Easily the best PS3 game I have ever played, Uncharted 2 quite honestly sets the bar for visuals, voice acting, writing, storytelling and overall fun factor for a console game, and if the single player wasn't epic enough, the game has a robust and addictive multiplayer component. Not only that, but we have a bevy of characters to care about, especially Nate Drake, our hero. Uncharted 2 is really an embarrassment of riches, and other companies should look to Naughty Dog for inspiration now.
The Elder Scrolls IV: Oblivion/Fallout 3 (PC/360) - *gasp* How dare I put two games in the same spot? I dare. The two games are similar enough, made by the same developer and I love them both so much that I don't mind if they share the same place on my list. Two epic open-world RPGs by Bethesda, two games that have sucked so much time out of my life (easily into the hundreds of hours).
Company of Heroes (PC) - Not much of a summary required. Not only my favorite RTS game of the 00's, but my favorite RTS game of all time; you command WW2 troops and you blow shit up. Fully destructible environments, period-accurate vehicles and weapons, and a cover system developed by the amazing Relic (creators of the Warhammer 40K franchise) make this game an awesome single player experience and a long lasting multiplayer experience. Relic does all they can to keep the game they released in 2006 up to date and stable, as if making a game that changed the face of RTS games today wasn't enough.
New Super Mario Bros (Nintendo DS) - A strange departure, as compared to my previous entries, but God I love this game so much. It hits the nostalgia nerve, but at the same time never stops being fun with new gameplay elements, a bouncy soundtrack and cool new environments. This is one of the few games where I went back and did everything: found every alternate route, unlocked every path, caught every elusive golden star. I was very disappointed that the sequel ended up on the Wii only (which isn't as fun, in my opinion) but I will still fire up my dusty DS and play my favorite levels from this game once in a while, and feel like a kid again.
Far Cry (PC) - A shooter that was ahead of its time in just about every way, Far Cry did its best to make me feel like a beaten down hero in a B-movie who is outnumbered, outgunned and fighting for his life. Visually, it was just better than anything that came out around the same time (yes, even better than Half-Life 2) and the AI would be unmatched for at least a few years. Yeah, the trigens brought it down a bit, but the overall game, the dedicated mod community, and the lasting fun I had playing the single player campaign over and over make it one of my favorite games of the decade.
Call of Duty 4 (360) - One of the most fun, addictive and engrossing shooters I have ever played. The multiplayer itself I have spent over 100 hours playing (I have a handy little leaderboard that tells me that) and the single player is no slouch either - as epic and over-the-top as a season of 24, with just as many twists and turns to boot. All games post CoD4 look at its example when crafting their multiplayer component now; even Uncharted 2 slapped on a persistent perk and weapons upgrade system, to keep the players interested.
Rome: Total War (PC) - There is a common theme running through my games, mostly with how much time they have sucked out of my life, and next to Freelancer, Rome: Total War stands as one of my most played games of all time. A big evolution in the series after Medieval, Creative Assembly tried to make the epic turn-based/real-time strategy game a little more accessible for the average gamer, while still keeping most of the depth for the hardcore fans of the series.
Grand Theft Auto IV (360) - It was a process of elimination for me to decide which GTA game would make it on my list, but in the end the choice seemed obvious (at least to me). Rockstar took all the minor enhancements from the previous games, threw in some amazing new stuff, blended it all together into one giant immersive environment and released one of the greatest games of all time. Sure the story is a little meh, and the characters really over-the-top but still trying to be serious, but the fact that Rockstar made this living, breathing city, and then improved everything the previous games were mediocre at (gunplay, driving, combat) lets me overlook those tiny foibles.
Honorable mentions
Rock Band 2 (360)
Gears of War (360)
Call of Duty: United Offensive (PC)
