Here's the list I was able to get from my bf:
2011: Dark Souls (honorable mention: Skyrim)
2010: Bayonetta (honorable mentions: Halo Reach, Mass Effect 2)
2009: Demon’s Souls (honorable mention: Modern Warfare 2)
2008: Rock Band 2 (honorable mention: SSB Brawl)
2007: Halo 3 (honorable mention: Mass Effect)
2006: Oblivion (honorable mention: Gears of War)
2005: Dead or Alive 4
2004: Halo 2
I was beginning to annoy him and I couldn't get the last two years but these are his choices. His overall game of the last decade would go to Halo 2.







