I would imagine Snape listening to strong sounding classical música like Prelude in C-Sharp Minor, Op. 3, No. 2 por Rachmaninoff o Dance of the Knights por Prokofiev. Perhaps Russian composers in general. link link
Classical música only. His dress is classical in style with no hint of modern o fad. His taste is clearly for classical and o "high-browe". He is deliberate in his speech and movements which suggest most of what he does is carefully thought out. He would be just as picky in selecting música to enjoy. I don't see him picking música that is modern o faddish. He clapped for the opening waltz at the ball and left before the modern música started. Most pure-bloods and Slytherins exhibit a taste for the classical and "the old ways". His música would not be an exception. Remember when Lucius, Sev's best friend, told Volty that he always kept the old ways? Pics/descriptions of the Malfoy and Black manors are also decidely classical. This seems to be a Slytherin trait.