Top Ten Films of 2003, in alphabetical order, top-heavy with epics (but it's not my fault there were so damned many amazing examples):
Angels in America (far too cinematic to be relegated to the Glowing Box)
Bubba Ho-Tep
Camp
Down with Love
Kill Bill
Love Actually
Master and Commander
Once Upon a Time in Mexico
Pirates of the Caribbean
The Return of the King
Technically released in 2002, didn't make it to me in Europe till 2003, and deserving a place on the above list, in order of preference:
Confessions of a Dangerous Mind (Belongs in the top five at least, if not higher)
The Quiet American
Whale Rider
The Dancer Upstairs
Honorable Mentions, in order of preference:
Secondhand Lions
Intolerable Cruelty
The Hours
Finding Nemo
X-Men 2
Mystic River