For me personally it was the Tandy Model-100 for a short stint, and then for quite a few decent years, it was the Atari Portfolio. I took that thing everywhere

For me personally it was the Tandy Model-100 for a short stint, and then for quite a few decent years, it was the Atari Portfolio. I took that thing everywhere, used it to write tons of code, kept all sorts of notes on it - it was truly 'my' computer in that it stayed with me at all times, which was very unusual back in those days ..