Which OS to Use for Postgresql

Which operating system should I use for a Postgresql server?

Linux?  Which version?

Other?

I do database work for several medium size companies.  They have about
100 users per company.  One has 3 different locations.  All woul dlike
to put some data on the internet, both publish and input from the
internet.

Is there anywhere that discusses configurations for postgresql?

Thanks,

Al