Agreed about Mr. Brooks, though I still do love that film. The song 'Vicious Traditions' by The Veils used at the end is actually one of my favourite ever songs. And great to hear you love The Machinist, got a huge poster of that on my wall.
Out of those three I'd say A Scanner Darkly because it's really unique and there's nothing quite like it. The others are good too, Blindness is a film that slipped under the radar a bit but it asks some thought-provoking questions throughout and Fermat's Room is a flawed but fun little thriller.
I didn't do too well with that list if you've seen all of them but 3 haha.