I host about a dozen services across my home lab and my VPS, but CopyParty takes the cake.

Having a WebDAV enabled a server that can generate thumbnails for photos, allow browsing through them, serve as an audio and video player, and also acts as a markdown and note-taking server has been immensely valuable. I write several apps that can write themselves back to the server over WebDAV sort of like tiddlywiki, so the overall combination has been extremely useful.