Awesome article. Been trying to tune it up a little, and now i'm getting a 403 in the directory documents, here is my full site.com config:

server {
listen 80;
server_name www.site.com;
#rewrite ^/(.*) http://site.com/$1 permanent;
access_log /var/www/site.com/log/access.log;
error_log /var/www/site.com/log/error.log;



location / {
root /var/www/site.com/public/;
index index.html index.htm index.php;

}

location /documents {
root /var/www/site.com/public;
auth_basic "Access restricted.";
auth_basic_user_file /var/www/site.com/private/pass;
}

location ~ .php$ {
# root /var/www/site.com/public;
fastcgi_pass 127.0.0.1:9000;
fastcgi_index index.php;
fastcgi_param SCRIPT_FILENAME /var/www/site.com/public$fastcgi_script_name;
include /usr/local/nginx/conf/fastcgi_params;
}


# redirect server error pages to the static page /50x.html
#
error_page 500 502 503 504 404 /error/error.htm;
# location = /var/www/site.com/public/error/ {
# root htm;
# }

}

Permissions on the directory are:

drwxr-xr-x 3 admin admin 4096 Oct 22 15:15 documents