Living with a girlfriend who doesn't like extreme music, I listen with wireless headphones quite often, but mostly not more than an hour a day and then often, also with headphone, when she's gone. So only through the speakers when she's not home, which doesn't happen too much, since we've got more or less the same working hours.
Got an mp3-player which I use at work, or I check out new stuff on youtube and such at work. Used to use my mp3-player on the bus as well, but stopped doing that for the same reason as acsenger. Also, going by bicycle to work, I don't listen to my mp3-player while riding. Would have to put it too loud and don't feel safe, because I also listen a lot whether cars are approaching. And judging from seeing other cunts ride their bicycles while listening to their mp3-players, I guess they shouldn't do it either.
For work I also sometimes have to ride around with cars, so if I know that from before, which I mostly do, I always take some CDs with me.
Whether it's noise or metal or anything (except for ambient), I listen to most music anywhere.