I suppose quotability is in the eye of the beholder, but yeah, I think Princess Bride qualifies by almost any metric.
Many films have a single strikingly memorable line, like Treasure of Sierra Madre, Scarface, or Gone With the Wind. Others have memorable dialogue throughout without having distinct one-liners. Sometimes there's a movie with memorable lines, like "Flaming death is a huge hit!", but I get the feeling that's more of an inside joke in our family.
But when it comes to a film with one-liners that have been adopted into popular culture and language. Princess Bride is about as good as it gets. Thank you, William Goldman.
Others that come to mind:
Monty Python and the Holy Grail Pulp Fiction The Godfather Star Wars Toy Story Airplane Tropic Thunder Forrest Gump Office Space Ghostbusters Spaceballs
Older films:
Cool Hand Luke The Wizard of Oz Dr. Strangelove Casablanca
I own this film and just saw it again. Here's my favorite lines:
'I know something you don't know. I'm not left handed either"(then his fencing starts to kick a**)
"Inconceivable!" "Why you keep saying that. I don't think it means what you think it means".
"My name is Julio Rodregous. You killed my father. Prepare to die." "Stop saying that!' " No! You killed my father you son of a bitch!' (And he right then finishes him off)
"There's a difference between mostly dead and all dead. Mostly dead, that means he seems dead but is still slightly alive, and we have a chance to bring him to. Now all dead, there's only one thing you can do, go through his pockets for loose change'.
Nothing more quotable than film noir. Watch Out of the Past, Double Indemnity, The Maltese Falcon, and The Big Sleep, just the most quoatable of many. And the great neo-noir Chinatown. Though nothing beats Casablanca (which has quite a few noirish elements, though it's not really a noir).
I've literally just finished watching this film so how quotable it will be for me personally, only time can tell. However, when I post that I was becoming obsessed with it a few people started commenting quotes so I'm guessing it is very quotable.
Another quotable film that no one has mentioned is Mean Girls. I think everyone under thirty quotes that movie a lot.