Rope and Rear Window are classics, of course, but my favorite Jimmy Stewart/Alfred Hitchcock collaboration is Vertigo. For some reason, I find Stewart at his most compelling when he played characters who teetered on the edge of psychosis, perhaps because he seemed so square and conventional on the surface. Scotty was emotionally fragile from the start of the film, and watching him fall deeper and deeper into delusion is entrancing. Vertigo is one of those films I make a point of watching at least once a year, along with North By Northwest.