Got a few projects in mind, according to intended hostname.
"Hecate": Mostly finished, VLB AMD 5x86, PC DOS and OS/2 (go Big Blue). At this point I need a 2MB graphics card (ET4000/W32i on the way, making do with a fairly good Cirrus GD5428 for now) and I need to do a small hardware mod to the motherboard to enable the x4 multiplier, since the CPU is currently underclocked to 100MHz. Not satisfied with the case, which is currently a modern Fractal Design minitower. I've got the power switch and turbo switch modded in the way Phil did in his 486DX2 Sleeper video, and it works a charm, but I'd rather have a desktop case.
"Metatron": Half-finished Super Socket 7 machine, K6-III+ CPU, Win98 and 2k (and NetBSD for when it needs to pretend to be modern). It's assembled and ready to start testing and configuring. I need another optical drive to fill the open 5.25" bay, or else I need another bay adapter and another floppy emulator. I have a Matrox G400 MAX and a Quadro4 380, not really sure which one to go with. The Quadro is obviously the more skookum card, but there's something about the Matrox that I always liked. I had one way back when, and I know there are some games (FF8 comes to mind) that have some issues with newer GeForce and Radeon cards, but run just fine on the G400. I'd love a Voodoo3, but I can't seem to find one for a price I wanna pay.
"Circe": Socket AM2 XP box. Pretty modern, all told, and almost new enough that I'll start hitting AHCI-related weirdnesses while installing XP, but it should work. I've got a Phenom II CPU, 8GB of RAM and a Radeon 6770 for it, now I need to come up with storage, optical drives, case and PSU.
I have a few other projects in mind for "dream machine of year X" rigs, but those are more pie-in-the-sky, since I don't really have the parts waiting in the wings yet. I do have a 386+486 motherboard that might be worth resurrecting, and three more working 486 chips that are kinda calling out to be used, though. (An SX/25, DX/33 and one that we thought was an AMD DX2/80, but turned out to be another AMD 5x86/133 when we got the heatsink off. Can't complain. The DX2/80 is rarer, but the 133 is a mighty fine Socket 3 CPU.) I'd swear there's an old Slot 2 Xeon floating around in here somewhere too, but I'll be scuppered if I can remember where, so...
Main Box: Ryzen-TR 1900X | GTX 1050/Radeon RX 580
98/2000 Box: PIII/766 |Quadro4 380 XGL