Well a lot of the foreign language films I haven't seen (or in lots of cases saw too long ago). The following are ones that I've seen recently enough to have clear enough recollections to form valid opinions, and I'll put them into two categories ("good, but not a masterpiece in my opinion" and "not my cup of tea"
)
Good, but not a masterpiece in my opinion:
La Règle du jeu (Rules of the Game)
8 1/2
Seven Samurai
Battleship Potemkin
Bicycle Thieves
La dolce vita
The 400 Blows
La Strada
Nosferatu
Umberto D.
Ashes and Diamonds
Not my cup of tea:
Jules and Jim
Grand Illusion
Cries and Whispers
La Belle et la Bête
Of course there's lot of English language films that fall into one of those two categories for me also.