I think that the Commodore Vic 20 and the 64 inspired people to realize that they would be able to play games on a computer.
In the 70's/80's, my father used to bring his computer home from work on the weekends. It basically filled the back seat of the car but he was using it for work and all I ever saw was the green text.
The first time I saw a Commodore Vic 20, then 64,
I thought past the 1's and 0's and thought I could enjoy spending hours and hours playing games on this.
For me, these were the first "consoles" that made me think outside of the computer=work mindset.
Awesome! I remember my friends had the Commodore 64 and myself the Amstrad CPC 464. Must admit, I was always a little jealous, but my machine was great. :)
My first was a TI99
I too was always jealous of my neighbour with the Commodore
Source
Now, you have me thinking ...
The first game I can remember playing obsessively was Alpiner
and I remember my mother getting hooked on Munch Man
If you feel like playing these on your PC, they can be found here as well as an emulator http://mntnweb.com/oldcomputers/ti994a/ti994a.htm