@esbeeb - Thanks for reviving this thread and injecting some interesting points. While your statement about ARM inferiority is clearly a little controversial, you certainly make good points regarding the low price of electricity and the value of my own time.
@tkaiser - Clearly you have some history with esbeeb and I appreciate you providing a counterpoint on the ARM inferiority issue. Having said that, what I'd really appreciate is if you actually weighed in on my OP.
I've thought about this quite a bit since my original post. I have to say that @Wdavery's post made a lot of sense to me. The biggest problem with the "1 big server" approach is that it puts all my eggs in one basket. I don't have the resources to build a server cluster, and even if I did, I don't want a jet engine in my office with me. -- (Having said that, from a noise standpoint, it's interesting to note that my primary (rackmount) PC and media server together are less noisy than my DGS-1024D switch! I intend to put a fan controller in that noisy bastard soon!)
OTOH, I can't really just go with several SBC-based servers because I need something with some power for Emby transcoding. And even if there's a high-powered SBC that could do the transcoding, there's still the issue of connecting 12-16 SATA drives to an SBC. (And that's an issue I already have resolved since I already have the server case and PCI SATA expansion cards - I just need to update the anemic motherboard and processor.) A hybrid approach seems to make the most sense. I LOVE how cheap and ubiquitous a RasPi is. If the SD card dies, no worries - it's backed up and I have spares on hand. If the Pi itself dies, a replacement is dirt cheap and BAM! I'm back in business. If my (x64) media server fails, well, that's a bummer, but frankly, I can live without Emby/Radarr/Sonarr/Lidarr/Calibre/photo server (TBD) a whole lot easier than I can live without Home Assistant (gods forbid I should have to go around at night shutting off lights and locking doors!) or my Ubiquiti controller, so Home Assistant (in a Docker container along with containers for Mosquitto, Node-RED, OpenZwave, Portainer, Watchtower, Pi-hole, and Ubiquiti controller) will live on a dedicated Pi and get backed up redundantly. I think I like the idea of putting NextCloud on a dedicated RasPi, too, and having that be my local backup destination for the Home Assistant server as well as the system drive for my media server (as well as serving Dropbox duties, of course). As for my self-hosted web server, I think it needs to be on it's own VLAN, cutoff from the rest of my network (too much risk there) - and while I want to have it up and running 24/7, I'd prefer it cost me as little as possible to do so - so I'll put it on its own Pi.