1. World of Warcraft
Easily the best experience I've ever had with a game ever. I played through the end of vanilla and all of Burning Crusade and I have so many memories. The game just felt like one huge adventure, every accomplishment meant something, bosses were tough and beating them felt awesome. Getting new gear from a raid was like the most exciting thing in the world to me. I was in a great guild with a lot of fun people and a lot of my friends played. There were so many things that were awesome about this game, I'm sad to think that the world I played in is no more but it was a great experience while it lasted. Not to mention it is easily the game I have spent the most time playing (roughly 50 days played).
2. Star Wars: Knights of the Old Republic
I love Star Wars. This game let you live out your own Star Wars adventure however you wanted. The characters were awesome, the mission structure was great, and all the force powers were cool. It was challenging as well. Most importantly, your actions dramatically changed what happened in the game. The story is just, awesome,it would make a better movie than episodes 1-3. Also the plot twist was insanely cool (even though my friend and I jokingly guessed it). Definitely the best single player experience I've had.
3. Half-Life 2
The best single player FPS out there, hands down. I don't care what people say about the pacing, when one moment you are shooting saw blades at alien zombies with a gravity gun, then the next you are mind controlling ant lions to attack combine soldiers, then you are dodging a space laser from the sky followed by shooting guided missiles at striders...the variety of gameplan is just the best there is. The story, although crazy and confusing is also somehow amazing to me. One of the few games I have beaten twice.
4. StarCraft II: Wings of Liberty
Blizzard just makes amazing games. I never even liked RTS very much before this game, and never could I even imagine understanding such a complex and competitive game, but Starcraft has been quite the experience. I still play it quite often, I have sunk well over hundreds of hours into the multiplayer. The single player was awesome, the missions were fun and the story was good. Not to mention this game has gotten me to watch live streams of pros, go to the MLG championship, and continuously watch GSL matches. The community around this game is awesome and as a complete package I'd have to say Starcraft 2 is NEARLY a perfect game.
5. Pokémon Red/Blue
I played Blue Version, because everyone knows Blastoise crushes Charizard in a fight. I have beaten this game 4 times and have went on many adventures trying to catch em all (I believe my fast was 89). I love this game so much that I started playing it again 2 years ago. It just never stops being fun.
I have many awesome genesis games, but vectorman is by far my favorite. For whatever reason I thought this game was the coolest thing when I was a little kid. Maybe its because you change into a bunch of awesome different things (like a bomb, a drill, a fish, and a train for starters) and I thought the "graphics" were soooo good. Also I probably played it about 500 times, and when I finally beat it after about 4 years of trying it was the greatest accomplishment of my young life, I was the happiest kid on the planet.
7. Star Wars: Rogue Squadron
One of the reasons I love this game so much is because my dad, who doesn't really like video games, would play this game. He actually beat it before I did. Also I replayed every level about 100 times trying to get perfect scores. Sometimes I would just go into a level and try to blow up every single object or building that could be blown up. Yes, that is crazy, but I loved doing it!
8. Jak II
Jak and Daxter was an awesome platformer, and Jak 3 had the best story and overall best gameplay (the ending was amazing) but the transition between 1 and 2 is what makes this game my favorite of the 3. The change from a Super Marion 64 style game to a more kid freindly GTA was just awesome. An open world with tons of missions, you got guns, raced speeders, had a hoverboard you could do tricks on, Jak got to speak, and the platforming was still top notch. Oh and he got dark powers, and the story was crazy good. Its the only instance of anything where I accept time travel as being a good plot element. Awesome game and an awesome series.
9. Batman: Arkham City
Yes, I gave Skyrim my goty over Batman. At the time I was in love with Skyrim ( don't get me wrong I still love that game) but after it being a few months since the two came out Batman stands out in my mind the most. The combat system is near perfect, and personally I have always wanted to fly around a city as Batman. Also it has my favorite ending of all time. When all is said and done this game will be in my memory the most from 2011.
10. Grand Theft Auto: Vice City
Probably the first "Mature" game I was allowed to play and man was it awesome. I still have the city memorized, I completed every mission, bought every piece of property, and just felt like a total badass while playing it. Also, the soundtrack is crazy good. The best GTA game in my opinion, (though I didn't play that much of IV).