A couple of classics that aren't.
Stalag 17 (Billy Wilder, 1953). It's based on a play, and you can tell. This isn't in itself a deal-breaker, but we're not exactly talking A Streetcar Named Desire here. William Holden stands apart from the cast, as does his character, and perhaps it's appropriate that he won the film's only Oscar. But there isn't a lot of competition in the movie (he beat a very impressive group for the Oscar: Brando, Richard Burton, and cancelling each other out, Montgomery Clift and Burt Lancaster in From Here to Eternity). No, in Stalag 17, Holden is up against what I imagine was a who's who of "hey, it's that guy!" for 1953: Peter Graves, Neville Brand, future sportscaster Gil Stratton. Not to mention Robert Strauss and the immortal Harvey "Eric von Zipper" Lembeck, whose mugging, especially from Strauss, may have played well on the stage, but who are tiring in the film. Otto Preminger pops in every once in awhile as a more competent Col. Klink. The reference to Klink is on target, considering the plot of Stalag 17 would have fit right in as an episode of Hogan's Heroes. The movie is better than I'm making it sound ... if you could eliminate Strauss' character, I'd even call it enjoyable. But I can't say I'm happy with the ending, where Holden's pseudo-antihero is accepted as one of the guys. If Stalag 17 isn't as good as Wilder's best, it is at least far better than One, Two, Three. 7/10.
To Catch a Thief (Alfred Hitchcock, 1955). The kind of movie where Cary Grant romances a woman (Grace Kelly) half his age (in fairness, it's really Kelly's character that romances Grant's). It's an odd film for Hitchcock, with barely any attempt at suspense. The French Riviera looks marvelous ... the movie's only Oscar went to Robert Burks for Color Cinematography. You can't blame Burks for the worst scene in the movie, when Hitchcock combines a fireworks display and some Grant/Kelly kissing into something that looks like it was concocted by a first-year film student. To Catch a Thief is pleasant to look at, and it generally keeps your attention. But it's not the first Hitchcock movie I'd recommend to a newcomer. 7/10.