I’ll second Matrix, Shawshank Redemption, Goodfellas, and Groundhog Day.
Also, the 1990s were the second period of great Disney animation - The Little Mermaid (1989) just missed, but what about Beauty and the Beast, Lion King, and the early Pixar efforts? Those films, and the great Japanese animation of the same era, revived a moribund genre.
ETA: Red Barchetta mentioned the two Toy Story movies.
Wow-- I forgot about “Irma Vep” from that list-- def in my top 5 of the decade. I’ll also throw in Kieslowski’s the Three Colours Trilogy, Any Given Sunday, Ashes of Time, and Breaking the Waves.
Goodfellas
Boogie Nights
Fargo
The Fugitive
Terminator 2
And then there’s 1999 from which five of my picks come. That was a seminal year for movies, the likes of which we haven’t seen since.
American Beauty
Magnolia
The Matrix
Fight Club
Office Space
I’ll also throw out honorable mentions to 12 Monkeys, Dead Man Walking and The Shawshank Redemption.
Don’t know if I would call some of the following the “best”, but they’re very re-watchable:
Pulp Fiction
Beauty and the Beast
Silence of the Lambs
Clerks
Unforgiven
JFK
Forrest Gump
Titanic
Saving Private Ryan
Apollo 13
Goodfellas
T2
Boyz in the Hood
Jurassic Park
Schindler’s List
Groundhog Day
ID4
Twister
Office Space
Magnolia
Reservoir Dogs
Fargo
Big Lebowski (that was '90s, right?)
From my Netflix ratings(out of 1,467 total ratings), I gave the following 90s movies either 4 or 5 stars:
5 Stars:
Fight Club
Groundhog Day
Pulp Fiction
Seven
12 Monkeys
4 Stars:
American Pie
Babe
Braveheart
Croupier
Dead Man
Face Off
Falling Down
Fifth Element
Frequency
Forrest Gump
Friday
Galaxy Quest
LA Confidential
Last Action Hero
The Matrix
Pleasentville
Trois Couleurs: Rouge
Sixth Sense
South Park: Bigger, Longer and Uncut
Speed
Terminator 2
There’s Something About Mary
Tombstone
Total Recall
Toy Story
Toy Story 2
True Lies
Usual Suspects
Trois Couleurs: Blanc
Shawshank Redemption
Silence of the Lambs
Saving Private Ryan
Goodfellas - Right up there with The Godfather as the best mob movie of all time.
Princess Mononoke - With its breath-taking animation and surprisingly nuanced and mature handling of the various sides in the conflict, this is perhaps the greatest animated movie ever.
Schindler’s List - Slightly over-dramatized, but still a masterpiece of human and epic storytelling.
Lock, Stock & Two Smoking Barrels - A heavily-stylized noir caper flick, it’s great fun to watch right from the start all the way through to the end, but it’s also carefully plotted and meticulously executed so as to make re-watching an endless treat.
Silence of the Lambs - A psychological thriller that benefits from one of the most chilling performances of all time.
Being John Malkovich - Bizarre, compelling, with fascinating characters and a great thought experiment executed magnificently. Extra points for the awesomely disturbing puppet show near the beginning.
Babe: Pig in the City - A dark and clever adventure with that child-like sense of horror and wonder, probably the best talking animal movie ever.
The Shawshank Redemption - It’s hard to imagine that a movie whose main theme is passing time with dignity could be so loved as to take the #1 spot in the IMDB.
Before Sunrise - About 90% of this movie is two characters talking over a ~16 hour period, and it somehow manages to be one of the most convincing on-screen romances ever.