My first Linux-first setup was a Pentium Pro 200 on a Tyan Titan ATX motherboard, which I bought sometime in 1997. At the time and with the 16-bit perf issues and the Pentium II coming out, the prices had dropped like a rock, but for 32-bit only Linux it was great.

Over time added more memory, a second CPU, and so on, and it was a workhorse through all of college. Held onto it well into the P4 era, as most of the upgrade options would have been a departure from SMP, which felt like a miss.