The World Ends With You with 55.33%
Shin Megami Tensei: Persona 4 with 62.3%
Portal with 67.4%
Final Fantasy XII with 69.1%
Skies of Arcadia with 54%
Mass Effect with 73.77%

Metal Gear Solid 3: Snake Eater with 77.77%
New Super Mario Bros. Wii with 58.88%
Paper Mario with 66.35%
World of Warcraft with 68.81%
Metal Gear Solid 4: Guns of the Patriots with 66.01%
Diablo II with 70.33%
Metal Gear Solid 2: Sons of Liberty with 71.50%
Shadow of the Colossus with 65%

The Legend of Zelda: Majora's Mask with 85.94%
Chrono Cross with 62%
Mario Kart Wii with 55.11%
Pokemon Gold/Silver/Crystal with 75%
The Legend of Zelda: The Wind Waker with 57%
Assassin's Creed II with 62.22%
Paper Mario: The Thousand Year Door with 58.9%
The Elder Scrolls IV: Oblivion with 63.5%

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I predict and analyse the Game of the Decade contest here:
http://www.gamefaqs.com/boards/8-gamefaqs-contests/56817040