I write primarily on my commute to work - netbook + 1 hour train ride = awesome writing time for me. I put my headphones on, zone out, and write like crazy.
For a year or so, I was living only 20 minutes from the city, and developed a curious discipline of getting down to writing as soon as I sat down on the train. It was the only way to get anything productive done in 20 minutes. I much prefer my hour-long commute (and was quite happy to keep it the last time we moved house, for this reason!).
At home, I really struggle to focus if I'm in the lounge (or near a TV/my desktop PC that I use for gaming). I find that curling up on my bed with the netbook is the best way to get anything done at home.
I love the netbook for writing because it fits into my handbag, and the screen is too small to do anything more exciting than text, so I don't go wandering the internets too much.
I have a pet coffee bar / restaurant that I use during NaNoWriMo for write-ins (which we now do once a month all through the year), and I love how productive I am there. However, it's a 45-minute drive from my house, so I think I need to cultivate a pet coffee shop closer to home that will let me plug the netbook in for a few hours. Perhaps I should go test a few local places out, hmmm.