(Emphasis mine.)
D’oh! Was hoping no one would catch my bad! 
The taking of Pelham 123
Artice 99
What’s the Marilyn Monroe movie… Seven Years Itch?
What about imaginary numbers? If imaginary numbers are legal, we can use any movie with “I” in the title…
Apartment Zero
Which, BTW, has a great movie game the characters play. But thats for another thread.
The Seventh Seal
The Seventh Sign
37°2 le matin (aka Betty Blue in English)
Two Women
1900
With Six You Get Eggroll
ThisYearsGirl, you crack me up!
You might be right about 200 cigarettes. I am too lazy to go check it out right now.
What really struck my funny bone was that you found a missing zero in one of the movies I mentioned, yet you failed to notice that in that very same OP I had included two movies which you proceeded to list again in your post.
Anyhow, what are the odds on someone having such a specialized attention span? 
Using imaginary numbers. Pretty imaginative of your part!
Nonetheless, as stated in the OP for the specific example of one, the number must be acting as such to be considered acceptable. Thus you will have to find a movie where I plays the role of an imaginary number instead of a pronoun. Good luck dude!
You found a loophole in my initial guidelines. Are you a lawyer?
Anyway, I love that movie so I will allow it. In that vein, all abbreviations qualify for this list. And of course that means a couple more nominees:
MI2
T2
More Sandra Bullock proposals
Love Potion #9
If 2 by sea. Not sure about the name. The movie sucked big time and I forgot most anything guarding any relation to it.
“100 greatest lesbian action scenes”
from my, ahem, friend’s, adem, collection.
I must have missed it, because I can’t believe no one on this board has posted 9 1/2 Weeks yet.
I’ll add Six Degrees of Separation and First Blood.
Come one everybody! We’ve got work to do. According to IMDB there are almost 450 movies that have the word “first” in their title. We are at least 2000 movies short of a complete list. Think! Think!
You’re allowing those even though they explicitly break one of the rules you set out in the beginning (2 indicating a sequel)?
Anyway, my contributions:
The First Power
Two Days In The Valley
And I may have to add Rambo: First Blood Part 2
THespos - someone did post 9 1/2 Weeks. Sorry.
Kilt-wearin’ man - I think it’s 2 Days in the Valley.
oldscratch - Do you mean the 10th Kingdom?
10 Things I Hate About You
1969
High Noon
I apologize if anyone has already posted these, but I checked as well as my apparently feeble eyes could manage, and I didn’t see any of them up there yet . . .
First You Cry
The First Deadly Sin
First Target
Murder in the First
First Strike
First Family
The Prisoner of Second Avenue
Second Time Around
Second Chance
Air Force One
Deathrace 2000
Transylvania 6500 (shudder)
The Adventures of Buckaroo Banzai Across the 8th Dimension
Farenheit 451
Oodles of ordinals:
The Third Man
Close Encounters of the Third Kind
The Fourth Horseman of the Apocalypse (not sure if this was really a movie)
The Fifth Musketeer
Henry V (several versions)
The Sixth Sense
The Sixth Day
D-Day, the Sixth of June
(I already posted the only seventh movies I could think of)
The Six Wives of King Henry VIII
The Private Life of Henry VIII
Le huitième jour
Can’t think of any ninth or tenth movies
Brewster’s Millions
Sinbad’s 7 Voyages, or The 7 Voyages of Sinbad, can’t remember which way it is worded.
Okay, let’s see…
10
10 Things I Hate About You
Sixteen Candles
18 Again!
976-Evil
Attack of the 50 Foot Woman
Mystery Science Theatre 3000
The 7 Faces of Dr. Lao
North Dallas Forty
You are oh so right, delini8r - what a horrible movie!