Apple Mac Mini G4
At some point I splurged on the novelty of having a computer in the kitchen for looking up (and storing) recipes, music, everyday web access, family photo slideshow when idle and, eventually, a computer for the kids to do homework. Since my wife has been an Apple fan for a long time (even before that on MC68000, two-floppy toasters) a Macintosh made sense. Apple's new Mini line made even more sense to me since, unlike the iMac, you didn't throw away an expensive monitor every time you upgraded. (We're on our third Mini in that location.) But this one was special because it ran a Motorola PowerPC 7447A, one of the "G4" (generaton 4) CPUs. Its eventual downfall was the tiny 256 MiB of RAM I bought it with and then upgraded to 512 MiB. A half GiB just wasn't enough for Mac OS X 10.4 and a few applications. However, it seems to be a fine platform for a headless Linux system.
IEEE 1275 (Open Firmware) makes installing Linux on this generation of Apple products easy peasy. Hold down the strange key sequence of <Command>-<Option>-O-F during the boot process to hold at the Open Firmware prompt. I installed Debian 8 which still supports 32-bit PowerPC hardware. It works quite well and even has enough performance I could use it as a lightweight server.
I don't have any internal photos of this machine because it's quite difficult to get into the case and I don't want to risk breaking any of its fiddly plastic tabs if I don't have to. The Mini's convenient, compact size comes at the price of difficult maintenance, mediocre cooling, an external laptop-style power supply and almost no configurability.