Thanks for your feedback davies.

A few of my friends use Pis for the same reasons you do. I've got one as my main media centre running Retropie. It's got a 2TB hard drive attached and shared across my networks for all of my video libraries, along with several legacy video game emulators. I have one other one in another room as a media centre client.

I then have one dedicated to doing 24x7 continuous integration unit testing on my RPi::WiringPi and the vast majority of children distributions it manages.

I've got two for development, an additional one for unit test staging and one running my indoor grow operation (App::RPi::EnvUI). I then have two Raspberry Pi Zero Wifi devices running MotionEyeOS, that backfeed to a central unit as wildlife/security cameras.

Update: I use Kodi as my core multi-media platform.