I like Suspiria but prefer Bird with the Crystal Plumage, which has superb contributions from both Storaro and Morricone. The story is also more coherent, based in the "real world."
I've seen two other Argento movies, Tenebre and Profondo Rosso. PR has a genius reveal at the beginning, but the movie itself is underwhelming (watching the longest cut didn't help). The cinematography lacks depth of field and vibrant colors. Tenebre is pretty good for cheap thrills.