If you've already got an OpenSolaris based NFS server, you may be interested in serving iSCSI targets. For me, this is incredibly useful with the right network configurations and a machine running KVM based virtual machines.

When picking out a solution for your central file server, there is of course many options. None of them quite stack up to the ease of administration and redundancy, out of the box, as OpenSolaris and ZFS provide. With ZFS you can build cheap storage arrays with disks of varying size and different levels of redundancy. For this setup I'm going to go with a basic raidz configuration using 4x 1TB SATA drives.