It was the spring of 1987 (April IIRC), and it was an Amiga 1000. My previous computer was a Microcom II+ (Apple clone) and I had been wanting to get a Mac because I was reading Apple-related magazines, but then I saw the Amiga and... WOW! I never, ever regretted going Amiga.
Since then, I have had an A1200, A3000, a PC running Amithlon and Linux, and now a Sam440ep.
I still have all of the mentioned machines.