External storage was a tape recorder (and watch that volume control otherwise the data transfer gets hosed !). I wrote BASIC programs, and a lot of assembly code video games. Come to think of it, I learnt some of my first AI techniques on this machine.
I also got an early lesson in technology envy; a friend of mine then acquired the 128k Spectrum, and thus I went very quickly from king of the hill to insanely jealous second-best :)
This nostalgic rant was brought upon by this site, allegedly one of the oldest continually running websites on the web.