I am using the Hiawatha web server to host content at http://www.linuxprogramming.ca/
, and have found it to be very secure and easy to use --- all in addition to it being fast. I have studied the source code to Hiawatha, and have found it to be very well written. The documentation and provided configuration files are also very well written and easy to understand. I particularly like how the all of the configuration options are outlined in a single manual page (with references to other manual pages, as required). This has allowed me to have a fairly comprehensive understanding of the server in a short period of time, as well as enabling me to make good technical decisions concerning what technology stack and how to implement it.
Thank you, Hugo, for the most fantastic webserver
P.S. This is a refreshing change from the overly complex nightmare that is apache.