What most people probably don't know is that Dr. Watson's name wasn't originally "Dr. Watson".
The original name of the diagnostic tool was "Sherlock", whose icon was a lit drop-stem pipe. I remember chatting about the Doctor with its author, the late Don Corbitt, whose office was just a few doors down from mine. In 1991, he had to change the name from "Sherlock" to "Dr. Watson"; I had forgotten why, but Danny Glasser came to my rescue and reminded me that there was already a debugging tool called "Sherlock" that had come out a few years previously. The name had to change, and the Doctor stepped in to fill Sherlock's shoes. The icon was originally a doctor's bag, but it changed to the stethoscope-wielding general practitioner a few months later.
You should also check out Matt Pietrek's reminiscences about Dr. Watson.
A note about Don Corbitt. He was a tall fellow with a deep booming voice, but he never used it. Instead, he spoke in a gentle, reassuring tone, backing it up with code that was always solid. I consider it an honor to have worked with him. Taking up the mantle of keeping the Doctor up to date with the latest forensic techniques, I updated it (i.e., rewrote it from scratch) for Windows 98. I was not a member of the Windows 98 team but wrote the program as a favor to them at great personal cost. (My then-boss didn't approve of my little side project and made his displeasure known at my next performance review.)