My brother had a Commodore PET, which he got in about 1980. It had a built in monitor that was about 8", an external cassette tape drive, and the memory was measured in kbs - I think he expanded it from 8kb to 16kb. I thought it was the bees knees, and my mates couldn't believe we had a computer at home!
There was one of these in the background in The IT Crowd (a familiar comedy series for those in the UK).

Beginners, on the home computing front ;>)... Sinclair Spectrum 48 and it's still working today (ca 1982), got it right when it came out peeking, poking with thermal printer (it smelled) and microdrive. http://en.wikipedia.org/wiki/ZX_Spectrum

Started out with a Commodore VIC-20, the predecessor of the Commodore 64. Must have been somewhere around 1983-85.
It had a whopping 5 KB of memory, 1 MHz CPU and 176 x 184 graphics (colors: green, amber or white).

But still a lot of fun

http://en.wikipedia.org/wiki/Commodore_VIC-20

My first programmable device was a Texas Instruments SR52 programmable calculator, that could read small magnetic flexible strips.
I received it as a gift from my father in 1974.
I learned the basics of programming computers with that machine. It could store 225 instructions, and had 20 memories. The battery was dead in less than an hour when running programs. So it had to be always on the wall socket, and could become very hot.
I used all my spare time to program that little machine.
After more than a year, my father seeing that I was completely mad at that machine, offered me a thermal paper printer that Texas Instruments had designed as optional equipment for that calculator.
The most complex program I designed was for playing chess. The program was never finished (that was really too much for this little machine) but was split into about 12 magnetic strips and took ages to run as you needed to reload, unload etc. You could play a few moves that's all. But just to reach that you can imagine that my room had the walls covered by long paper strips (2mt long) with program printouts.
When I think back over those times, we were pioneers. After all the Apple II came out a few years later.

A small addition to my initial post. The first desktop PC type machine I worked on was tha TERAK 8510. This was during my studies in 1979. It had a graphical monochrome screen, and I used it to create a software that allowed graphically to build simple DC electrical circuits with discrete components: resistors, inductors, capacitors, diodes etc. and it would calculate voltage and current values on all points of the circuit.

My real first personal desktop computer was the first Macintosh II I bought in 1987.

Apple II with 4K memory, in 1978. Expanded to 16K in 1979.

Although I didn't own it, an HP2000 in 1974 was essentially "my" computer as I was frequently the only user on it and definitely the only programmer. (I learned to program on that machine.) The Apple II was quite a step down and took some getting used to.

- D