Shadow of a Doubt (1943) vs Strangers on a Train (1951)

Strangers on a Train has more "big set-pieces" (Bruno's stalk of his victim through the amusement park; the tennis match/sewer cross-cut; and the spectacular berserk carousel), so I have to give it to Strangers on a Train for being a "bigger deal."

But Shadow of a Doubt has a rather incredible power derived from the simplicity of its suspense set-up -- a psychotic serial killer takes up residence with his sister and her family -- the movie runs on pain; the family is so nice, the Uncle is so evil...but loved deeply by his sister(always) and his niece(before she finds out her secret.)

These are both two of Hitchcock's best -- I give the edge to "Strangers" for its spectacle, but there can be no doubting the emotional power of Shadow of a Doubt.

Note in passing: Hitchcock gave us "one psycho per decade":

The 40's: Joseph Cotton as Uncle Charlie (Shadow of a Doubt)
The 50's: Robert Walker as Bruno Anthony (Strangers on a Train)
The 60's: Anthony Perkins as Norman Bates(Psycho)
The 70's: Barry Foster as Bob Rusk(Frenzy)

...each killer is more brutal than the one in the decade before. We never SEE Uncle Charlie strangle anyone. Bruno commits a fairly graphic strangling that cuts into a trick shot(the eyeglasses.) Norman Bates commits the most shocking murders in screen history to that date(the two butcher knife stabbings) and Bob Rusk adds rape to the mix ahead of strangling.

Thus, Joseph Cotton as Uncle Charlie has to generate menace and fear without a murder scene. He does it.