Home server Operating system?

I'm building a home server on HP DC7800 SFF with a core2 quad q6600, 8gb ram and 8TB of total storage, what OS is best, i own copies of home server 2011, 7 pro, and 8.1 pro, it needs to do some virtualization, plex, torrents, and backup storage, minecraft, and all without having to use a monitor

Added (1). WHS 2011 turns End Of Life 4/12/2016

Added (2). I'm very familiar with Ubuntu, Debian, and all the distros based off those

If it was mine I'd probably use a server version of Linux which would make it less vulnerable to attack and malware. However, you've got Windows Server 2011 so that'll probably do the trick, and it may also be more familiar and therefore easier for you to use.

Edit: it sounds like you know just as much as me about this so maybe you should trust your own judgement on this.