For stupid web apps that serve content straight from cache, or for servers that are very I/O bound (like anything involving messaging) ... then Node.js may blow Clojure out of the water.

For everything else ... i.e. most startups I see on HN ... you really have to take the CPU-bound or synchronous logic out of Node.js, otherwise it sucks big donkey balls.

People striving for the ultimate development experience have really forgotten what it's like to have brute processing power. Web apps like PlentyOfFish which had 1.2 billion page views/month in 2009 ran only on 2 balanced web servers ... and this considering that on a dating site everything's dynamic, you really can't have too much caching.

Clojure might turn out to be the best of both worlds ... a productive programming language coupled with the brute CPU-bound performance that the JVM can yield.