Halo 3 certainly had the biggest hype and biggest launch of the year.
Bioshock was the biggest surprise, amazing atmosphere, great game. And that opening rivals the intro to Half-Life. What a great setup. Would you kindly.
Although Stalker was just as big a surprise as Bioshock. That game really kept me on my toes. True survival FPS.
Uncharted was great to have something colorful and lighthearted to offset the anxiety Stalker induced and a great adventure on its own, yet Uncharted 2 is where it really clicked. The latter part of Uncharted went a bit off the rails.
Mass Effect was awesome, still the best in the series to me. The controls and combat weren't as refined yet, however the story and progression in the first game is still the best of the series. Those Mako controls though lol.
Super Mario Galaxy, Super Paper Mario and Portal are all in my all time top 50.
Portal gets my vote, sits the highest as the most original and simply awesome puzzle game.
The game is so polished, perfect difficulty curve with stylized hints and instructions. And then the banter.
It was topped by Portal 2, both are classics. Best video game song and end credits as well.