Best year so far. My memory is getting fuzzy so I skipped a few games.
Civilization 4 – Still the bar for civ games.
GTA San Andreas – Ambitious, but probably overly.
Freedom Force vs the Third Reich – Sadly ignored series of games.
KotoR 2 – Just as good if not better than the first.
Resident Evil 4 – First game in the series I liked and it was the first mostly action game.
Forza Motorsport, Gran Turismo 4
God of War
Splinter Cell – Whole series is good, consider all of them Honorable Mentions
Psychonauts – A bit overrated, but quirky and fun.
Jade Empire – If only the combat were as cool as in early builds.
FEAR – Goofy plot, but fun FPS.
Half Life 2 – I never got into HL1’s single player, but this was adequate.
Prince of Persia Two Thrones
Indigo Prophecy – Trippy supernatural story wrapped in a decent adventure game. A bit too many quick time events though
Fire Emblem Sacred Stones
Mario and Luigi Partners in Time
Hearts of Iron 2
Sly 3: All around good series of games.
Doom 3 – Honestly didn’t see what the big deal was.
Quake 4 – Same as above.
Fire Emblem Path of Radiance: Worst of recent Fire Emblem games.