My favorite movies:

Monty Python and The Holy Grail
Kung Pow
Space Balls
Blazing Saddles
Dazed and Confused
What's Eating Gilbert Grape
Office Space
Monty Python's The Meaning Of Life

Plenty more..I just can't think of any right now.

I agree with all of teenagelectric...
But I would add...

The Skeleton Key,
The Science of Sleep,
Vanity Fair,
and ummmmm...
Aqua Teens Hunger Force !

For me, the best movies I seen are the Saw trilogy and the two Hostel movies.

The Godfather
Empire Strikes Back
Rope
Silence of the Lambs
Lord of the Rings:The Return of the King
The Full Monty
A Clockwork Orange
North by Northwest
Suspiria
Dawn of the Dead (1977)

These are the films I consider to be the best of each decade (in no particular order):

Before 1960:

- Vertigo
- Citizen Kane
- Rear Window
- On The Waterfront
- The Wizard Of Oz

1960s:

- Midnight Cowboy
- Bonnie and Clyde
- Easy Rider

1970s:

- The Last Picture Show
- Five Easy Pieces
- Taxi Driver
- Nashville
- Patton
- One Flew Over The Cuckoo's Nest

1980s:

- Raging Bull
- Mask
- Terms Of Endearment

1990s:

- The Ice Storm
- The Sweet Hereafter
- Clerks
- American Beauty
- Pulp Fiction
- Chasing Amy
- Fargo
- Sling Blade
- Forrest Gump
- What's Eating Gilbert Grape
- Leaving Las Vegas
- Good Will Hunting
- Heavenly Creatures
- The Brothers McMullen
- Titanic


2000s:

- Brokeback Mountain
- Hard Candy
- About Schmidt
- Lost In Translation
- The Girl Next Door
- Adaptation
- Bridge To Terabithia
- The Squid and The Whale
- Little Children

This is hard. Not all of these are favorites, nor are they in any particular order, but I do consider them of the highest quality.

All About Eve (the script is absolutely perfect}
Citizen Kane (technically flawless)
Sunset Boulevard
Duck Soup
Dinner At Eight
Stagecoach
Psycho
My Fair Lady
The Red Shoes
La Dolce Vita
Dr. Strangelove
Star Wars
Amelie
2001: A Space Odyssey
Modern Times
Chinatown
Mildred Pierce
The Shawshank Redemption
Crouching Tiger Hidden Dragon
King Kong (the original of course)
Rebel Without a Cause

and more. These are the ones that come to mind first.

Star Wars - All of them, but the original trilogy is better.

Stardust

Pirates of the Caribbean - All of them

The Sound of Music

Transformers

The Piano

Monty Python - anything

In no order >>> #1 Back to the Future #2 Magnificent Seven #3 Escape from Alcatraz #4 The Rock #5 A Beautiful Mind #6 A Bronx Tale #7 Enemy at the Gates #8 Good Will Hunting #9 Platoon #10 Serendipity #11 Rounders #12 Saving Private Ryan #13 The Hunt for Red October #14 Breakfast Club #15 Dances with Wolves #16 Color of Money #17 Glory #18 Last of the Mohicans #19 Road to Perdition #20 Gladiator #21 Ice Station Zebra #22 Apollo 13 #23 The Godfather #24 Dogday Afternoon #25 Bridges of Madison County #26 Million Dollar Baby #27 Ray #28 The Big Red One #29 Scarface #30 Return to Paradise ---- Thanks, Ken