Here is an interesting P4 build which I plan to replicate someday. It was my childhood build and was sort of a late Win 98 but early XP era build.
A Pentium 4 2.4 GHz (socket 478) build with 256 MB of RAM. It was built around late 2003. It most probably had an Intel motherboard but I am not too sure about that. The storage was a paltry 40 GB HDD with 2 partitions of 20 GB each for the OS and the other stuff. I also had a floppy and CD drive. In addition to that, we had a Logitech keyboard, mouse and speakers. We had a modem card for dial up connections and a HP printer for printing my dad`s office documents. The case was a black one(I forget the manufacturer) and the peripherals too had the same color except for the white HP printer. I also remember the huge CRT monitor which was always set to 1024*768 resolution and went lower for games.
Coming to think of it, I do not know why my family did not get more RAM for the system. Also we did not have a GPU even though we could have gotten one. We eventually upgraded the RAM to 768 MB and the HDD was replaced around 2010. XP was such a great OS that it felt snappy even on that old machine and it ran quite well till 2012 before the ageing power supply exploded and caught fire. I think the internals of the system might have survived that mishap but we chucked it away/put it in storage for portable laptops.
During the time I had the system, I played games like Diablo 2, FIfa 98/2001, Max Payne, Halo CE, Project IGI, NFS Most Wanted, Prince of Persia WoW and SoT, Aoe 1&2, Warcraft 3, Starcraft 1 and GTA SA/VC. I even remember using an old software called 3D-Analyze to run PoP Sands of Time as it had some weird Nvidia GPU requirement. I also learnt programming using BlueJ, jdk and Borland C. It was also fun to mess around with Clippy in Office. I think people seriously underestimate how great XP was as an OS and how little it`s memory footprint was compared to the later offerings from windows. Another feather in it`s cap was the great reliability. It was an idiot-proof OS able to take any abuse from a toddler to a moody teenager.
Minimum or low end spec XP is quite fun. I do have an overpowered XP system now and it is good to enjoy my collection of old games at crazy FPS and high definition audio, but there is something magical in trying to run those games on a 640*480 resolution without a GPU.
Edit: I just heard that the cabinet and the motherboard/cpu might still be around. The peripherals though are long gone along with the CRT. Maybe I can resurrect the build if the motherboard is still working.