I guess I can post here, now, too
I hit the 50k mark today, and though not officially registered anywhere I think I can still declare myself a NaNoWriMo winner.
I've actually loved the experience and am really excited about the story I've started. I guess I'm about halfway through the first draft, so I will plough on and finish it. At this writing pace it will needs loads of reworking, re-writing, editing etc. As well as a massive amount of research. But that's been the case with anything and everything I've written. I've always adhered to the "writing is rewriting" philosophy.
Anyway, the number one thing I've learned is something I knew anyway, so it was reinforcement rather than learning: don't wait for inspiration in order to write, sit down and start, and soon you will find that inspiration.