Back to the Futures I and II
Superman I and II
The original Star Wars Trilogy (to the point where I can recite some of the "alien" dialogue. i.e. Greedo in the infamous scene.)
Scream
Wizard of Oz
Dumb and Dumber
Ferris Bueller's Day Off
Home Alone
That Thing You Do
Star Trek VI: The Undiscovered Country

Probably many more. That's just off the top of my head.

TBSR reciting Greedo dialogue. That I'd like to see!

Blazing Saddles
Johnny Stecchino (the English translation of course)
Many Three Stooges shorts
The Party

Great question though!

Actually Jabba dialogue is a little easier, as it seems to be spoken slower, particularly in the "new" Jabba scene. (The fact that every time The Daily Show does a Jabba joke, they quote "Han mah bookie" from the Special Edition rather than anything from his original appearance in Jedi would seem to back this up.)

Fun fact - when they shot Jabba's scenes in Jedi, the puppeteer spoke all the lines in English and operated the mouth accordingly. Thus, if you read the subtitles, you'll see Jabba's mouth movements correspond to the English equivalent of what he's saying in Huttese.

Big Lebowski
Fight Club
Happy Gilmore

Anchorman
Forgetting Sarah Marshall
Role Models
Garden State

Apollo 13
The Matrix
Back to the Future 1
The Wrath of Khan
It's a Wonderful Life
Mr. Smith Goes to Washington
Armageddon
The Fifth Element

Raiders of the Lost Ark (hands down my most watched movie of all time)
Back to the Future
Die Hard
Glengarry Glen Ross
True Romance
Michael Clayton

A movie critic (I want to say it was a pre-Salon Matt Zoller Seitz but it could have been someone writing for the Hartford Advocate in the mid-90's) talked about how some movies he'd seen so many times and were so good that he'd put them on as soundtracks/white noise while doing housework or writing or other things. That after so much repetition and re-watches that they worked like a movement of classical music - he wouldn't need to see them at all, but based on music cues, sound cues, explosions, or dialogue, he knew exactly where and how far along he was in the narrative.

Most of the movies on my list I can even visualize the edits and cuts and transitions as they occur in my head just by listening to them.

Rear Window
The Treasure Of The Sierra Madre
The GodFather Part 2
The Empire Strikes Back
Groundhog Day
Rounders
Aguirre: The Wrath of God
Rashomon
True Romance
Pulp Fiction
Goodfellas
12 Monkeys

Star Wars
The Empire Strikes Back
Commando
The Lost Boys
Psycho
The Naked Gun

Akira
Princess Mononoke
X2: X-men United
Casino Royale
Starship Troopers
Gladiator

Breakfast at Tiffany's
The Breakfast Club
Bring It On
Can't Hardly Wait
Clueless
Dazed and Confused
Ferris Bueller's Day Off
Funny Face
The Princess Bride
Wet Hot American Summer

Back to the Future
Office Space
Rushmore
There's Something About Mary
Toy Story

Two that I haven't seen in about 15 years that would have qualified in my younger days are The Mighty Ducks and its sequel, D2. I remember my brothers and I would pick which characters we were going to be each viewing and we'd all recite their lines as they were happening in the movie.

My wife hates it when I'm muttering dialog under my breath as the actors do so on screen. Among the most egregious of my bad habits:

The Matrix
The Godfather
Jaws
Star Wars
Repo Man
Raiders of the Lost Ark
Airplane!
Blade Runner
Hunt for Red October
Just about every Pixar movie...

Zulu
Rocky
Casablanca
Back to the Future
Rocky Horror Picture Show
A Fish Called Wanda
My Cousin Vinny
Breakfast Club
Broadcast News
Field of Dreams
and so many more...

As a younger writer, my picks tend to skew towards newer movies.

10 Things I Hate About You
Lion King
Aladdin
Beauty and the Beast
Star Wars Prequels (though I still can't help myself from cringing during some of the dialogue...)
The Fugitive
There Will Be Blood

Warning: this is a long list...

Ed Wood
Boogie Nights
The Exorcist
Pulp Fiction
Reservoir Dogs
Jackie Brown
When Harry Met Sally
Jaws
Dumb and Dumber
Zodiac
Session 9
Jacob's Ladder
A Nightmare on Elm Street
LOTR: Fellowship of the Ring
White Men Can't Jump
The Social Network
The Shining
Rosemary's Baby
The Dark Knight
Pumpkinhead
The Omen
Shutter Island
Deliverance
Psycho
The Departed
The Others
The Blair Witch Project
A.I.
The Assassination of Jesse James
The Truman Show
Terminator 2
Alien
Seven
The Talented Mr. Ripley
Mystic River

Pretty much anything in my small DVD collection, but off the top of my head:
The original Star Wars trilogy (eps. 4-6)
Clue
The Crow
Breakfast at Tiffany's
Robin Hood: Prince of Thieves (Alan Rickman!)
Tron
The Little Mermaid
Aladdin
The Emperor's New Groove
The Jungle Book + several other Disney movies
(big Disney kick in high school)
Army of Darkness
The Fugitive
Moulin Rouge
Serenity
Stranger than Fiction
Labyrinth
The Dark Crystal
The Princess Bride

When I was in grade school, my friend and I held a tape recorder up to the TV and recorded Clue, then played it all the time - easy to memorize that way! Aladdin came out when I was in the throes of a Disney obsession and I sat in front of the the TV w/ a notepad and hand-transcribed all the dialogue (didn't have a computer/typewriter). I guess I do crazy things in the name of fandom :)

The Fugitive
The first three Indiana Jones'
First three Star Wars
Aliens
The Matrix
True Lies
Robocop

And the three reigning champions are:
The Shawshank Redemption
Back to the Future
The Terminator

I know you've recommended not studying the same genre you're currently writing, but I've found it very useful. Hence the films and scripts that I'm watching/reading over and over include:

Terminator 2: Judgement Day
Aliens
Minority Report
Blade Runner

Star Wars
The Empire Strikes Back
Forrest Gump
Raiders of the Lost Ark
Animal House
Monty Python and the Holy Grail
Network
LA Confidential
The Good, the Bad and the Ugly
Pulp Fiction

The Original Star Wars trilogy probably word for word.

Gladiator
The Matrix
Small Soldiers
Jurassic Park
The Land Before Time (the original, not movies 2 through 24 or whatever they're on now)
Pirates of the Caribbean
Lord of the Rings

I'd be a little rusty with these, but I bet they'd come flooding right back:

Liar Liar
Jaws
It's a Wonderful Life
The Philadelphia Story

Off the top of my head.

The Fugitive
The Bourne Movies
Groundhog Day
Dave
Dumb and Dumber
Almost Famous
Dazed and Confused

Some Like it Hot
Sunset Blvd.
Double Indemnity
The Testament of Dr. Mabuse
Casablanca
Chinatown
The Maltese Falcon
The Matrix
For a Few Dollars More
Stagecoach

and undoubtedly...

The Big Lebowski

The Towering Inferno
The Poseidon Adventure ('72)
Superman ('78)
Peter Sellers' Pink Panther films
Raiders of the Lost Ark
Jaws
Airplane!
Airport ('70)
The Sound of Music
The Apartment

Some great suggestions. I'd definitely have to add "Monty Python and the Holy Grail" to my list. Interesting how so many of you mention Star Wars. Imagine human history without those movies! Thanks for your comments!

Off the top of my (somewhat embarrassed)head:

The Graduate
Raising Arizona
Spinal Tap
Toy Story
Star Wars

I think there's only two for me:

Pirates of the Caribbean I
The Princess Bride

This isn't my total "favorites" list (there would be about two dozen more...), but just the ones that, as Scott asked, I've seen so many times I can just about speak the dialog...

Raiders of the Lost Ark (pre-VCR I had the 2-album soundtrack that I would listen to over, and over, and over...)
Star Wars / Empire Strikes Back
Contact
Close Encounters of the Third Kind
Blade Runner
Unforgiven
The Sixth Sense
What Dreams May Come
Donnie Darko
Rocky
The Godfather
Jaws
The Breakfast Club
Say Anything

...and...don't laugh...but every time it's on, I have to watch:

Road House

Midnight Cowboy
The Elephant Man
Raiders of the Lost Ark
Ratatouille
Ed Wood
Deliverance
This Is Spinal Tap
Monty Python and the Holy Grail
Fanny and Alexander
Anchorman
Amarcord
The Sixth Sense
The Graduate
Groundhog Day
My Cousin Vinny
The Shawshank Redemption
Hot Fuzz
Shaun of the Dead
Fargo
The Apartment
What's Eating Gilbert Grape
Amelie
Days of Heaven
North by Northwest
Office Space
The Good, the Bad and the Ugly
Out of Sight
The Blues Brothers
Get Shorty
After Hours
Breaking Away

The Big Lebowski
Back To The Future trilogy
Star Wars Trilogy (IV - VI)
Fight Club
Home Alone 1 + 2
Jackie Brown
Pulp Fiction
Meet Joe Black
K-9 (yes, that's right ;)
Happy Gilmore
Clerks 2
The Matrix
American History X
Terminator 2
Aliens
Scream 1 + 2
Scrooged
Ghostbusters 1 + 2
Die Hard 1 - 3
The Fifth Element
Trainspotting
12 Monkeys
The Naked Gun 1- 3
Lord Of The Rings: The Fellowship Of The Ring
Batman and Batman Returns
Memento
Donnie Darko

and, yeah, thanks RonC: No... can't... avert... eyes... must... watch... Road... House

Many of the previously mentioned movies would make my list as well, but the one that immediately came to mind was Three Days of the Condor - to the point that my wife says "Hey, it's that movie you watch" when she walks into the den and sees it on screen.