I used mine as a NAS for a while with an external USB HDD and a samba share. It was also set up to be a VPN and pi-hole. I have a pi zero that I use to flash coreboot on laptops.

My PS3 isn't doing so hot as a media server client for my NAS's movie library - the network connection is poor, the interface is fiddly, and it can't load subtitles embedded in files. I was going to buy a pi3 to replace it as a media server client and hook up an external DVD player, but now I'll be getting a pi 4!