nginx

After migrating from Apache/mod_python to nginx/flup on a VPS my Django sites began responding up to 10 times faster; overall system load decreased significantly. I couldn't believe my eyes =)
After some months of testing I can say that, indeed, for a VPS this configuration is perfect. Not only nginx requires much less resources than Apache, but it's also much easier to configure.

You can read details about our experience here: http://blogs.sonatype.com/people/brian/2008/10/29/nginx-is-centrals-new-friend/

We rely on Nginx and Passenger to serve the Open Hub. It's been a rock-solid and reliable server that has been straight-forward to install and configure.