Vivitar V2000. Small, light, plasticky. Very simple; fully mechanical and manually controlled, with a +o- metering indicator, with the 'o' lighting up in green, the + and - in red. Such a brilliant idea. Pentax K mount. My first ever 'proper' cam, bought in 1992 from Vic Oddens in London Bridge, for £100 inc a 28-70mm kit zoom. Got me through my A level photography, which then led on to uni. Those two year son the A-level course were some of the best of my life. That camera enabled me to really fall in love with photography, and set me on a journey I'm still enjoying. Still got it; it still works! Probably the one camera I would never part with.
Nikon D600. Bought in 2013. Replaced a D200 I'd bought a few months previously, to get me back into photography, but which quickly proved too limiting. The D600 was an instant revelation. Enabled me to explore photography much more, and to really hone my craft. A brilliant camera, so capable, produces such wonderful results. Still got it, still using it regularly.
Nikon Z6. Bought last year. Bought to replace a D3300 which I'd bought for travelling etc. An
incredible camera. Where the D600 astonished me, this leaves me dumbfounded. It's low light capability, particularly, is just unbelievable. And it focuses on someone's eye; even if they're moving about!!!
It even focuses on a cat's eye!!!!!!!
I've had/have a fair few other cameras, some really good. Currently trialling both a Nikon F4 and a Canon EOS 1. Who knows, maybe I'll fall in love with one of them too. But the above 3 will do for now.