My first MacIntosh computer--the Mac Plus purchased in 1986 for somewhere in the neighborhood of $2500. Luckily I had it on hand in 1989 as a prop for a photo shoot with most of the original MacIntosh team for the 5 year anniversary (scroll down). In the photo are most of the people whose names were embossed on the inside of the plastic case. They're mimicking a familiar Steve Jobs hand gesture at my suggestion.
At that shoot I asked those present to sign the underside of my Mac. Here's a photo of that.
Among those not present at that event were Bill Atkinson, Burrell Smith and Steve Jobs. I frequently see Burrell Smith walking in Palo Alto and have tried to ask him to sign the computer but he refuses, and although I have photographed Bill Atkinson I forgot to bring the computer along. As for the Steve Jobs autograph--I did not forget to bring the computer on my last shoot with him. Here is that signature.