It was the Electron for me. Bought it new for the equivalent of less than #100 when Acorn discontinued it, the only computer I could afford from my allowance. Incidentally it also forced me to learn German and English as a kid, to be able to read the manuals and Acorn Magazine.
Second to learning to read, that machine probably had the largest influence on my career
Second to learning to read, that machine probably had the largest influence on my career