For what?
Movies, I generally keep everything flat, because (imho) that's the way the producer intended it to sound. They tend to sound very good on my system in my setting that way. But then, I like my speakers, and I have an acoustical room. If I am clearly lacking some level of response, or annoyed by a preponderance of anything, I might then cut or add as appropriate.
SACD is another story. Depending on how it was engineered, calibrating the response of each speaker can make the experience that more fulfilling.
I'm of the opinion that you first select a quality speaker that you enjoy, and place them appropriately in an acoustically friendly room. There should not be much need for equalization in that environment...at least not for movies.