My original Raspberry Pi model B I bought on release day, fighting the latency and downtime of the websites selling them. Never did much with it but was my introduction to SBCs.
What I actually use day to day are a Raspberry Pi 3 B+ which is attached to a 3d printer running Octoprint and a Pi 4 running as a small home server to host my NextCloud and IRC bouncer (amongst a couple of other things).
My favourite toy at the moment is actually my StarFive VisionFive 2 RISCV board, its been fun trying it out and getting applications to compile on it which don’t officially support RISC-V.