My newest desktop, an HP Vectra VL400:
Pentium 3 800MHz EB
256+128MB SDRAM (was 64+64 originally, maximum is 1x512)
80GB disk (original was a 10GB Seagate, rubber wrapped from the factory)
Full drivers available for every Win9x/2000/XP operating system, plus partial support for DOS/3.x; decent Linux support (needs a kernel recompile to enable the i815 framebuffer; I've actually thrown in a Radeon 7000 which surprisingly works better out of the box with the libre drivers)
Proprietary-shaped 120W power supply you'll never be able to find a replacement for (but standard ATX connectors)
Supports internal UPS that fits into an optical drive slot
Case designed for the motherboard, the leds/buttons connect and disconnect as a single connector, floppy and HDD area directly in front of their connectors; bracket cover for cards instead of screws
BIOS with descriptions for every option, and detailed full screen explaination of errors (including "idiot, you swapped the PS/2 devices")
By its 2001 standards this was actually a decently premium office PC, although I bought it in 2005 for 80 € and it's been my main second-home PC until about 2013