I've been trying to find ways to scale down and simplify my computer usage further. You can run an ARM system in the framebuffer for the minimalism, but at the end of the day, these are still very complex machines with a very complex operating system. I don't even inherently dislike GUIs and I'd even go as far as to say that pure X11 (without bloat-y libraries like GTK and such) is by far not the worst we have to deal with. I've got more of an issue with the sheer amount of code and silicon complexity everything builds on you just cannot avoid. Also the power consumption. Why does looking at website make my modern x86 CPU eat 50W?!
I have tons of retro hardware, some old, some not that old. Recently I put a small Z180-based DIY computer together, an 8 bit system with 512kb of RAM (although only 64kb are directly addressable at once in CP/M) and the entire OS in a Flash ROM and I actually fell in love with some applications for it. Wordstar made me change to Joe's own Editor on my regular PC and SuperCalc2 is an amazingly capable spreadsheet without all the dead weight. (I always think programs need to be simple, programs e.g. like emacs and vim are bad IMO because they're so obstruse, something a lot of linux software in my opinion actually suffers from, there's a lots of feature creep and cargo culting going on in the world of linux, but not many admit it) The power consumption is at the very most 0.1W-0.25W and I had to measure at the power connector of1 the board since it wasn't really measurable before the power supply. It can use SD-Cards for storage, there's a lot of tools to write programs in Pascal/Modula 2, Forth, Fortran, Basic etc. and you can easily write drivers for new hardware you designed yourself in an afternoon. The only downside is that you pretty much require a serial terminal, that OS was still made with things like the DEC VT-100 in mind, which will up power consumption in the end. There are cheap and low-powered solutions for that though. This computer is pretty much in in whatever flow I'll set up. The power consumption is so neglible and it's so easily used from whatever system via serial that letting it run 24/7 wouldn't hurt anything. There's emulators that run inside small atmega microcontroller, which would push power consumption into irrelevancy, although they'd probably be not as fast.
I also have a bunch of old DOS-era machines, industrial computers that are pentium era and performance, some really old 286s and almost anything in-between. I've never made a tally of what the power consumption looks like though. For the industrial systems it's probably pretty low. There's a lot of useful DOS software and tons of programming languages. DOS can be kind of arcane to program for though sometimes. The (lack of good) memory management is a PITA.
I also have a bunch of Amigas and C64s with a various amount of expansions. As much as I like it, I'd go as far as to say that the C64 is a bit too primitive to be useful besides playing some old games. The Amigas are quite different there and AmigaOS was far ahead of it's time, lots of ways to make it useful even today. I also have an old 68k Mac, but I honestly have to say I never thought the old Mac software was that good, many other systems did things better.
Not sure what I'll set up yet. I mostly want to be able to handle text, program, do a bit of organizing for my solo-roleplaying and connect to text-based online services which will probably require me to set up some very low powered linux SBC of some sort to be able to SSH out from. I also might set up an Android tablet or something as strict media consumption machine I can remote control from whatever I put together. Or maybe a Smart TV? I don't know anything about that stuff. So anyways, thanks for reading my blog. It's a bit dead here so maybe somebody will find this interesting.