Express, Async, Mongoose, Redis, Socket.io, CoffeeScript, Less, and Underscore, off the top of my head. We also use Node Inspector during development; that's a great little tool.

Really awesome. I'm using the same libraries right now in my own app and struggling hugely with Backbone. Would love to see some of the posts someone referenced a few posts up to explain how you fit it all together.

I am a bit curious about it's performance characteristics (e.g. number of node.js instances launched, method of load balancing, etc). Do you experience any problems with GC?