Rabbi Moshe Feinstein was against people listening to any music, since the Churban habayis (other than music at Simchas Mizva occasions).
Nowadays as there is more depression, some Poskim are generally more lenient, and allow people to listen to music when they feel low. However they say you should ‘not listen when you eat, and wake up’ -Rabbi Shraga Kallus explains this to mean, you should not walk around with I-Pod listening to music all day long- music should not be your whole etzem-this detracts from Zecher Lechurban.