LightHttpd vs Nginx [closed]
Both have pretty excellent performance. Using FastCGI with Lighttpd is a bit easier, because it is able to spawn processes by itself (downside is that it runs fastcgi servers as the same user as the webserver), while nginx requires a bit of manual work. Both are perfectly capable of acting as reverse proxy and load balancers.
If you need good performance, I'd also suggest to use nginx as front-end to serve static files, and Apache backend. While this requires more RAM, nginx+apache2+mod_php is somehow faster than nginx+php-fastcgi. I currently have no proof benchmarks, though, so take this statement with a grain of salt.
Also, IMHO nginx has somehow more human-friendly configuration file syntax, but opinions may vary.