I've started doing the same thing and recommend Witness for the Prosecution highly. Rear Window, Paths of Glory, and North by Northwest are others that have held up to modern eyes, IMHO.
I go back to watching North by Northwest every few months. The writing, the sets, the cinematography, the music and the acting all sublime. One of my favorite random facts is that Albert R Broccoli initially wanted to get Cary Grant for the first Bond film, but the producers ended up deciding to get a younger actor.