You guys have given me great advice in the past, so I thought I'd try again with a new system build.
Primarily, this system will be a LAMP server (Linux, Apache, MySQL, PHP) for my personal development projects. It will also serve as a CVS server and repository. I want to leave it up 24/7.
Secondarily, I thought I'd set it up as a NAS server as well.
Ubuntu 9.04 server edition. This will be a headless system, so no video card or sound card is required.
Are you going to be compiling code on this box? Or just CVS? If so you don't need such a powerful processor. An Intel Atom should be good enough and draw about 10% of the power of the system you speced out.
Also why RAID? Hard drives almost never fail these days. Its much more likely you get zapped by a power hit from lighting or somebody hitting a pole outside your house. It that case you loose both drives. You better off putting the second drive in USB dock, backing everything up to it, and putting it on a shelf.
Take a look at VortexBox. It's based on FC11 not Ubuntu but it makes a perfect NAS box.