My own personal cloud storage

I want to have a machine that acts as my own "drop box" for different files. I am just wondering what kind of hardware I would need to fulfill the needs of a family of four. Will likely mostly have movies and other media.

I would also like this machine to be connected via VPN. I don't want people looking at the data between mean and my machine at home and possibly getting into my home network. Is there an operating system or tutorial that shows how to do this?