I've been jealous of Write Room for the Mac for a while but now there are two Windows (or cross-platform) clones: Dark Room and JDarkRoom. They're all stripped down full-screen text editors:
It's sort of stupid that with all the amazing multitasking and features on the average desktop that a full-screen and nearly featureless text editor seems exciting and fresh. I think it reminds me of my days writing in Telemate. (Wow, there's no Wikipedia page for Telemate.)