So "perfect" here means "can be rewatched infinitely without much loss in enjoyment"? If that's the criteria, then there's so many I hardly know where to start, but here we go (alphabetical order):
Aliens (2nd movie)
As Good As It Gets
Back to the Future
Baraka
Battle Royale
City of God
Dark City
Die Hard
Erin Brockovich
A Few Good Men
Forrest Gump
Ghost in the Shell
Ghostbusters
The Godfather (1st one)
Good Will Hunting
Gran Torino
Groundhog Day
Guess Who's Coming to Dinner
High Fidelity
Hoosiers (no one has mentioned this yet? seriously? it's a friggin' basketball board...)
Howl's Moving Castle
The Hunt for Red October
Indiana Jones and the Last Crusade
Jurassic Park
The Karate Kid
Kill Bill (vol. 2 especially)
Kung Fu Hustle
Life of Brian
Lord of the Rings (all of them, but particularly the first)
The Matrix
Millennium Actress
Monty Python and the Holy Grail
Mr. Holland's Opus
My Neighbor Totoro
Ninja Scroll
Ocean's Eleven (2001)
Paprika
Porco Rosso
The Princess Bride
Princess Mononoke
The Remains of the Day
Rounders
Samsara (2011)
Sanjuro
Schindler's List
Searching for Bobby Fischer
Seven Samurai
The Shawshank Redemption
Spirited Away
Swiss Family Robinson (1960)
Star Wars (4 and 5)
Terminator 2
Tokyo Gore Police (amazing for what it is, which is a cheesy gore-fest)
Vampire Hunter D: Bloodlust
Whisper of the Heart
Who Framed Roger Rabbit
Willow
...and I'm sure I'm forgetting stuff.
EDIT: Forgot Ghostbusters, added it to my original list.