I have an old netbook I will be converting into a file server for my home. Centralizing photos, video, and music is the only concern or priority, and I would love to enable auto backup/sync from our phones.

I have access to MS server 08r2, and Linux is free. Apparently OSX will also run on this netbook. So in theory, I can choose any OS. I want a set it and forget it solution, so what is my best option?