Good question. I use Ubuntu Gutsy Gibbon and have some nice disk encryption tools, ssh tunnels for my email and other routine communications, and Tor for firewall circumvention and rudimentary privacy, but I'd love to know more, too. Go to it in the comments.
I write books. My latest is a YA science fiction novel called Homeland (it's the sequel to Little Brother). More books: Rapture of the Nerds (a novel, with Charlie Stross); With a Little Help (short stories); and The Great Big Beautiful Tomorrow (novella and nonfic). I speak all over the place and I tweet and tumble, too.