The website I'm working is allegedly going to have a massive hit rate soon after launch. The client is talking about the possibility of 3,000 hits per second over a day or so.

Ignoring the fact that this hit rate is probably wild client optimism and apart from getting the largest servers possible, what is the best way that Drupal should be configured to support a large hit rate.

I've read Scaling the drupal.org Infrastructure, Drupal performance blog, Best Practices for Scaling Drupal and many other pages, but what I'm looking for is real experience of doing this, what works, what doesn't, and what to expect.