I've found my lifeline when it comes to writing in a house with eleven people. And it's right here, at http://www.whitenoise.fm/
Actually, I like the brown noise option better, but either way, it's lovely. None of the distraction of music (which, yes, can be a distraction if you can procrastinate like I can), but all of the noise-blocking goodness. Even great with my broken headphone jack (stuff still plays out the main speakers even with the headphones plugged in), 'cause it's background-ish and everybody just thinks it's my dinosaur laptop constantly running it's fan, which is a thing that is normal. I've cranked out almost two-thousand words today, to a story that's been giving me loads of trouble. (Which is great, because it's my Defy the Dark contest entry, which is due in like three days. Yes, not done yet. Yes, I'm pushing it. Shut up.)
Only downside is, when you take the headphones out, the real world feels terrible quiet and odd, like when you're used to sleeping with a fan and then, for some reason, you can't. But other than that, lovely.