If you are using an nginx server as a reverse proxy cache for apache I would like your feedback.
I have created a plugin that clears the nginx cache when you update a post. It is available at http://wordpress.org/extend/plugins/nginx-proxy-cache-purge/
This plugins requires that you have ngx_cache_purge module installed with nginx.
Please reply and let me know if you have used this plugin and if it is working for you or if you have any questions. Also, please let me know what features you would like to have added to this plugin.