My first was a 1977 JMP 2204, which I got for £400 about 15 years ago. I think it's still the best sounding amp I've played through! I got a Vintage Modern 2266C combo around the same time, and it's still amazing too.
After numerous Gibson, Sunn, GK, lots of Fender + clones, L6 DT25 & 50, Mesa Mini and a Satellite Barracuda [still have] I bought my first - a 4210 in 2014 and it's been mostly Marshall since.
My 1st and only Marshall so far is my Origin 20H. Before that I only used Crate amps (outside of my little Fender Mustang 1) since the early 90's. I got rid of my last 2 Crates and got the Origin shortly after.
A 1977 Marshall JMP MKII 50 Watt in Fawn. Man I miss that amp, if not the weight. I broke (at least) three handles over seven years carrying that amp. Always manage to catch it before it met the pavement, however.
....an old 100w Marshall head in the early 80's when I was in my early teens. I have no idea what it was other than that. I'm pretty sure it had a Master Volume.
Many years later (early 2000's) my neighbor brought over a '79 JMP 2203 and I bought it for $400. Sold that a couple years later.