What, nginx is not fast enough for you? Well, if you have a very high load that's quite possible (although unprobable :P ). I've learned and tested quite a few things about nginx optimization by reading this article:

http://blog.martinfjordvald.com/2011/04/optimizing-nginx-for-high-traffic-loads/

Most important points in there are probably fitting the number of workers to your # of CPUs, then optimizing disk IO with buffers. One thing that seemed to help me with this blog was to boost fastcgi_buffers up from the default value.

Since I'm using a somewhat recent version of nginx (more recent than the one in squeeze, at least), the open files limit at the OS level was of no concern to me.

Also, last but not least: most of the hosting providers don't actually want to disable access logging like the article suggests, since it can be very useful for detecting patterns when dealing with DoS attacks or other nasty things. But if you do want to reduce disk IO and can spare some network bandwidth, what you could to would be to send your logs on the network directly to a log aggregation server so that your disk is entirely freed up from this work. This can be achieved by different means and will be left as an exercise to the reader :P