Well, I never really completed many games until so inspired by my comrade in gaming, Roushimsx. 2006 is where it took off. This year just past was much slower than 2007 due to work, but I intend to remedy that in 2009. When you consider I played World of Warcraft on and off since November 2005, well, these lists don't seem so short, eh?

2008:
1204 - Gears of War 2 (360)
1129 - Professor Layton and the Curious Village (DS)
1113 - Halo 3 Legendary (360)
0824 - Patapon (PSP)
0714 - Disgaea: Afternoon of Darkness (PSP)
0620 - Metal Gear Solid 4 (PS3)
0524 - FF7: Crisis Core (PSP)
0405 - Devil May Cry 4 (PS3)
0218 - Company of Heroes: Opposing Fronts (PC)
0106 - Fire Emblem: The Sacred Stones (GBA)
0105 - Uncharted: Drake's Fortune (PS3)

2007:
1201 - Mass Effect (360)
1122 - Assassin's Creed (360)
1111 - Call of Duty 4: Modern Warfare (360)
1029 - Ratchet & Clank Future: Tools of Destruction (PS3)
1013 - Portal (PC)
1012 - Half-Life 2: Episode Two (PC)
0930 - Halo 3 (360)
0923 - Heavenly Sword (PS3)
0910 - Lego Star Wars II (360)
0907 - Rise of the Kasai (PS2)
0831 - Halo 2 (XBOX)
0829 - Bioshock (360)
0809 - Gears of War (360)
0722 - Ninja Gaiden Sigma (PS3)
0707 - The Darkness (PS3)
0702 - Rainbow Six: Vegas (PC)
0629 - Starcraft (PC)
0530 - God of War 2 (PS2)
0513 - Castlevania: Portrait of Ruin (DS)
0503 - Ratchet & Clank: Up Your Arsenal (PS2)
0417 - Rogue Galaxy (PS2)
0102 - Shadow of the Colossus (PS2)

2006:
1229 - Final Fantasy XII (PS2)
1223 - The Legend of Zelda: Twilight Princess (GC)
1028 - F.E.A.R. Extraction Point (PC)
1027 - Dark Messiah (PC)
1021 - Company of Heroes (PC)
1016 - Warhammer 40k - Dawn of War (PC)
0813 - Darkwatch (PS2)
0810 - Evil Dead: Regeneration (PS2)
0809 - Castlevania: Aria of Sorrow (GBA)
0730 - Prey (PC)
0715 - F.E.A.R. (PC)
0708 - Ghost in the Shell: Standalone Complex (PS2)
0625 - Mega Man Zero (GBA)
0603 - Half-Life 2: Episode One (PC)

Quite the sorry lists, here:
2005:
Advance Wars Dual Strike (DS)
Resident Evil 4 (GC)
God of War (PS2)

2004:
Half-Life 2 (PC)
Ninja Gaiden (XBOX)

2003:
Prince of Persia: Sands of Time (PS2)
Beyond Good & Evil (PS2)
Metal Arms: Glitch in the System (XBOX)
Star Wars: Knights of the Old Republic (XBOX)
Broken Sword: The Sleeping Dragon (PC)
Warcraft III: The Frozen Throne (PC)
Rise of Nations (PC)
Doom 3 (PC)
Far Cry (PC)