I write everything creative in WordPad. It's small, and simple (not a huge mess that looks terrible and fills up the better part of the screen, like Microsoft Word!) I can't write in notebooks, because my hands can't keep up with my head if I'm trying to write in pen/pencil-- not to mention that I start to get really painful cramps in my hand, as well. Plus, I can hang my WordPad document over an inspirational image, and turn on music, so the computer is most convenient.

Admittedly, I drag around little books or sticky notes or my sketchpad to jot notes in, in case I get a particularly good idea at an unfortunate time. I'll also write by hand if I really need to remember something.