Nest is using both C (for embedded Linux on the thermostat) and Python (some of the API services) they are also hiring for lots of positions, some are listed at nest.com/careers
Nest looks really cool and I like the idea of having a physical (as opposed to virtual) product. Are you interested in hiring any junior engineers? Feel free to drop me a line (my email is in my profile) or leave your email here, I'd love to chat.