My favorites are "The 39 Steps" (Robert Donat and Madeleine Carroll are both brilliant) and "The Lady Vanishes" (possibly the most perfect balance between comedy, romance and suspense Hitchcock ever achieved).
That’s mid-Hitchcock. :-) Early Hitchcock would be silent, and those are hard to find good DVDs of.
Years ago I bought a commercial VHS of this movie, and found the quality of the sound track distractingly bad. I wonder if newer releases have located a better sound track.
There wre two remakes; I saw the 1978 version with Robert Powell and David Warner and thought it was pretty good (for not being Hitchcock, that is).