I said that I'd write a post about headphones, given my latest headphone recovery project. I have a few thoughts about this so here goes...
I think having a good set of reasonably isolating headphones is one of the most important pieces of technology that an aspiring writer should have. Not ear buds, I'm talking big, over the ear headphones that block out most of the background noise. "Active Noise Canceling" isn't required (though mine have it, I don't often turn it on). And since you're likely to wear them a bunch, headphones that are comfortable have reasonably good sound quality.
A good set of headphones is to my mind, crucial for most group living situations, like dorms--particularly where there isn't shared music interests. Even if music selection isn't an interest, having headphones allows independent sleeping schedules and at least let me set up a more distraction free writing and studying environment.
It's kind of like the perfect personal office. And putting the headphones on can act as a personal marker to separate "work" and "play" times (particularly relevant for me as a writer, as "dicking around on wikipedia" and "writing," are not otherwise substantially contextually discrete activities.) Though I write whilst listening to music (I basically listen to music constantly) I do sometimes just use the headphones as sort of dorky earplugs, I'll confess: just to get the isolating and ritual effects.
It's possible to get the headphone effect with "real" isolation, and it's possible to establish rituals using other objects/habits, but it's harder. And you can't really argue with success.