I used to have the 15w Marshall Ministack which was a hilarious amp to own....wish I still had it. The JCM800 is still one of my faves (and it's the amp model I use most on my Valvetronix). Marshall shaped the sonic palette of rock and roll.
I had a 72 or 73 master lead series in the early 90's, meandered for years with other amps and finally would up back with Marshall. I got their "Vintage Modern Combo" a few years ago and am absolutely in love with that amp.