Good WiKi Engines

I've been comparing many Wiki engines to be put on my site. For PHP based with or without MySQL, I think DokuWiki and PMWiki should be best suited. TWiki is really good with a lot of features but it requires CGI::Session and a lot of tweaks at the server which will be a problem for non-root like me. DokuWiki also support USB version which is really neat. For more comprehensive comparison check out here