nginx - A high performance free open source web server powering busiest sites on the Internet.
Apache HTTP Server - Apache httpd has been the most popular web server on the Internet since April 1996
Microsoft IIS - Internet Information Services is a web server for Microsoft Windows
Cherokee - High-performance web server
UltiDev - UltiDev LLC makes server software allowing web applications to be distributed to, and hosted by non-techincal users: consumers and small businesses.
gatling - A high performance web server. Small! (125k static Linux-x86 binary with HTTP, FTP and SMB support).