TRS 80 model 1TechRepublic member OP Gene remembers: "My first computer was a TRS-80, Model 1. It used a cassette tape drive for storage. I wrote a program in micro-basic to balance my check book." (Steven Stengel explains at oldcomputers.net that T = Tandy, RS = Radio Shack, 80 = Z-80 microprocessor.)
Related Geekend post: Dust off that dinosaur computer.