Best configuration for postgresql (postgresql.conf)

Hello to all,
Im still new in this and I need some help. I have install correctly OSM server(with mapnik2) + apache2 + mod_tile on Ubuntu 10.04 Lucid 64-bit, but rendering is very slow and dont use all amount of RAM. I need help with configuration of - “/etc/postgresql/8.4/main/postgresql.conf”. Can someone tell me what is best(optimal) configuration for my machine - 1TB - HDD , 32GB RAM and Core i7-2600 CPU. I will be very thankful if someone can help me.