usually when people around here talk about using a Mac as a media server they're not also using it as media player--they have Macs or other devices, such as an Apple TV, that act as players connected to displays and then they have a centralized server, something that's on the network that all the other devices can call upon for media, so in that sense what video connections a "media server" has isn't really important. Set it up once with a display, then run it headless if you want and screen share in from time to time. As long as you wire it up over gigabit you should be fine, that'll make it easier and more responsive for the other Macs, Apple TVs and iOS devices to access over your home network. Of course, you can use a Mac as both a media server AND media player but that's up to you. Some choose a NAS to handle their centralized storage, but Apple wants you to have iTunes open and running on a Mac, that's why many of us feel there's value in dedicating a Mac solely to media server duties, it's very convenient having iTunes home sharing always on, your Mac Pro would do fine in this role, especially if you could tuck the Mac Pro out of the way in a closet. The main reason the Mini is so valued around here is because it is small and quiet enough to put right next to an HDTV, powerful enough to play the toughest blu ray and serve content to other devices, readily available as a refurb and still quite user customizable--you can easily add your own RAM and relatively easily install two of your own drives/SSDs inside. So do consider the Mini as your front end, but don't think your Mac Pro wouldn't be up to the task in the back end. It'll be a fine whole house media server.