Robert69While not necessarily Italian, two of my favorite horror films during the early 70s are "Blood for Dracula" and "Flesh for Frankenstein", both directed by Paul Morrissey. They have a great exploitation/art house feel, and Blood for Dracula is in my top 10 of all time.
For Italian Horror, Lucio Fulci and Mario Bava are some of the most revered, check out their top films.
If you're looking to get a 50s/60s/70s horror feel, pretty much everything Hammer studios did in those decades are pretty amazing, and there are so many to choose from.
If you're looking for a Hitchcock feel, also check out Carol Reed namely Odd Man Out, The Fallen Idol, and The Third Man...and Night Train to Munich as well.
If you're in need of directors with their own visual styles:
Nicholas Winding Refn's Drive & Only God Forgives have great night time/neon feels, as is the end of Harmony Korine's Spring Breakers.Gaspar Noe's Enter the Void is a visual punch in the brain, amazing, amazing movie.
Terrence Malick's The Tree of Life is just a beautifully photographed film.
Lars von Trier's Europa is a good modern-ish, black and white film, his films Dogville & Manderlay are also interesting with their lack of sets.
Reiner Werner Fassbinder's World on a Wire has a nice visual feel due to the 1973 interpretation of the future and the modernist feel of the time.
David Cronenberg's Dead Ringers has a great 80s modernist feel and style to it, especially in the costumes.
Panos Cosmatos's Beyond the Black Rainbow is a great interpretation of 1983 style done in 2010.
Steve McQueen's Hunger, a true personal favorite, has amazing visual style and tone.
Those films really stand out from the norm for me in terms of appearance and lasting abilities.
Is there something more specific you're looking for, like a definitive list of top Gialli style films or just something to kind of get the juices flowing?