I can't possibly choose only one, but here are my favorite games:

• Metal Gear Solid
• Final Fantasy IX
• Half-Life2
• Legend of Zelda : Wind Waker
• Devil May Cry 3
• Halo: Combat Evolved
• Elder Scrolls IV: Oblivion
• Mass Effect 1
• Sonic the Hedgehog 3
• Silent Hill 2
• Shadow of the colossus