In order to have a Audiophile-grade home set up, these are what you need:
Asus Xonar DG:
Xonar Unified drivers: http://brainbit.wordpress.com/2010/07/19/asus-xonar-unified-drivers/
Set the headphone amp of Xonar DG to max power and enjoy. This setup will blow away even some rigs ranging in $500+. Don't take my word for it, try it.