I considered these, but figured you'd post them. Seconds has one of the most gripping openings ever, I think. The ending is a knockout too. True Confessions (which Plaw would have surely praised in this thread, too) is a quiet, subtle, excellently-acted film.

I'd add three more, all from the same year, for now (more to come as I think of them)...

It (1927)
dir. Clarence Badger - amazingly sophisticated film in both film language and the way in which its in-film romance unfolds. Gains much from the star of its day, Clara Bow (what a knockout she is, too), who embodies the girl who has "it", an elusive something which attracts men.

Shooting Stars (1927)
dir. Anthony Asquith / A.V. Bramble - Charles Barr, a renowned authority on British silent film, called this the "mature silent cinema that speaks for itself". And it does, too. Innovate film grammar, deep self-reflexivity, and complex moral solution. A must-see, for definite.

The Unknown (1927)
dir. Tod Browning - Browning is probably noted most for Freaks (1932), but here he and Lon Chaney create an absolute masterpiece which I rarely (if ever) see in top 100 lists of American films. It's impeccable, in acting, lighting, and the dark, perverse narrative and the Freudian imagery. Unforgettable, once seen.