Holly (Audrey Hepburn) and Paul (George Peppard!) wind up together.
Long Version (Since there can't be just a short version for Breakfast at Tiffany's):
Paul Varjak (George Peppard) a struggling writer moves into a New York City brownstone apartment building and meets Holly Golightly (Audrey Hepburn), an impecunious, but beautiful and chatty, social butterfly. Holly invites him to parties and also to Sing Sing (the maximum security prison in the Town of Ossining, New York), where Holly is passing messages to mob drug kingpin Sally Tomato (Alan Reed) for $100 per visit. Paul becomes attracted to Holly, which puts Paul in conflict with "2-E" (Patricia Neal), his wealthy patroness who is supporting him while he tries to write another book.
When "2-E" complains to Paul that she is being followed, Paul meets "Doc" Golightly (Buddy Ebsen) who tells Paul that he is Holly's husband. Doc tells Paul that Holly's real name is LulaMae Barnes and that Doc intends to bring her back to Texas. Paul brings Doc to meet Holly who embraces Doc happily. Holly spends the night with Doc, but the next day she tells Paul that their marriage was annuled and she sends Doc back to Texas on the bus alone telling him, "You musn't give your heart to a wild thing".
After Holly's plans to marry a rich Brit named Rusty Trawler (Stanley Adams - Cyrano Jones to Star Trek fans!) go awry when Rusty marries a wealthy woman who can get him out of debt, Holly and Paul spend a marvelous day together walking around Manhattan, stealing cartoon masks from a five-and-dime store, visiting the New York Public Library so Paul can autograph a copy of his book (much to the chagrin of the librarian) and going to Tiffany's, where an understanding salesperson agrees to engrave the prize ring Paul got from the box of Cracker Jack that Doc was eating for Holly.
It is implied that Paul and Holly spend the night together when Paul awakens to find that Holly is not beside him in bed. Paul breaks up with "2-E", since he has fallen in love with Holly, but can't find Holly until he visits the public library where he finds Holly studying books about Brazil. Holly breaks Paul's heart when she tells him she will marry Brazilian billionaire José (whom Frank met at the party in Holly's apartment, along with Holly's "agent", O.J. Berman (Martin Balsam)) for Jose's money.
When Holly and José return to her apartment after a night of partying, she finds a telegram notifying her that her brother Fred was killed at an Army base in Kansas. Since Holly would not return to Texas with Doc, Fred was going to come to New York to live after he was discharged. Holly wrecks her bedroom in grief. Jose' appeals to Paul for help, but Paul declines, leaving Jose' to deal with her.
Several months pass. Paul has several stories published and has moved out of the brownstone, but Holly invites him to a going away dinner at her apartment. She is leaving the next morning for Rio. When Holly botches cooking the dinner, they go out to eat, but when they return, the police are waiting to arrest them after being tipped off by Holly's perpetually irritated, oriental neighbor upstairs, Mr. Yunioshi (Mickey Rooney!?!?!)
Paul calls O.J. in Hollywood and O.J. bails Holly out, calling her, affectionately, "a phoney, but a real phoney". The next morning Paul has Holly's clothes, purse and cat and is waiting with a taxi when Holly is released on bail. Paul also has a letter from José stating that Jose' is ending their relationship because of her very public arrest.
Holly plans to jump bail and go to Brazil despite Paul's heartfelt entreaties. Holly throws the cat from the taxi into the pouring rain which brings Paul to pay the cab driver, stop the cab and get out. As he stands in the rain with the door open he calls Holly a "chicken" and tells her "You've got no guts. You're afraid to stick out your chin and say, "Okay, life's a fact, people do fall in love, people do belong to each other, because that's the only chance anybody's got for real happiness." He leaves the cab after tossing the engraved ring into her lap.
Holly cries, leaves the cab and runs to find Paul, who is searching for the cat. Holly finds the bedraggled feline between some crates in an alley. She walks back to Paul and the two soaking wet lovers share one of the most iconic kisses in big screen history.
Thanks Evil Ed!