Best OS for Postgres 8.2

Hi,

I am about to order a new server for my Postgres cluster. I will
probably get a Dual Xeon Quad Core instead of my current Dual Xeon.
Which OS would you recommend to optimize Postgres behaviour (i/o
access, multithreading, etc) ?

I am hesitating between Fedora Core 6, CentOS and Debian. Can anyone
help with this ?


Regards