Since about '89: an A500, rev 5. Used it until being replaced by a 486 in '93. Replacing it with a pc was a good choice. Yes, it really was. The A500 desperately needed replacing and the choice was between a more recent Amiga and a pc. The pc won, obviously.
Since then, I sold the A500 and got me several other Amigas as retro computers (A1200, A2000, A3000). And although I still prefer my pc for normal day-to-day stuff, the Amiga is much nicer to fool around with.