Some Like It Hot is a five star classic, with Tony Curtis and Jack Lemmon in drag, and Billy Wilder writing and directing at the top of his game. The Seven Year Itch has her most iconic scene (though the actual shot in the film is not what you've seen on posters) and generally considered 4 and a half stars. The Misfits and Gentleman Prefer Blondes are very good four star films, with the Misfits having the added mystique of being Gable's last film (he died two weeks after filming wrapped) and the last completed film by Monroe, with an excellent pedigree: a script from Arthur Miller (written around the time he divorced Monroe), support from Montgomery Clift and Eli Wallach, among others, and direction from the legendary John Huston. It never reaches the heights you'd expect from gathering such elements together, but still unique. Those first four are good no matter how old you are. The other five range from good to average, with no real turkeys in the mix, but none coming near the previous films I mentioned. If you're at all curious at why she's such an icon even today, about half a century after her death (and want another reason to be jealous of Joe DiMaggio and Marlon Brando, among others), check it out. They're definitely worth $4 each.