What are, in your opinion the most important models of walkmans in history (not only Sony)

I wish I had better memory and could remember what threw the switch. Back in the 70's it was really cool to have a tape recorder and record songs from your radio so you could play them whenever you wanted. This was very low-fi with a tape recorder, the kind with a few piano style switches, sitting next to a radio. While stereo was cool the reality in the US was that most broadcasting stations were on the AM (mono) dial and the smaller cool stations were on FM (stereo) but there was only a few of them, not like today, only five or six, and they were playing either only very current songs (look at top 10 from the 70's, no AC/DC, Led Zeppelin, Who, etc) or classical. The boombox and Walkman helped change this landscape, not only could you bring cool music with you and play for everyone on your boombox and in stereo! but you could also buy prerecorded music on cassette tapes (also on stereo). My vote goes for the app killer, the TPS-L2, after that it was about size, battery life and build quality. Sure there were some killer units but they were basically professional units, no kid or college student would ever own one of these, personally I never knew they existed until I found this site 15 or so years ago.

For my little town, small Sony's were King, everything else was a knockoff although AIWA did have a great reputation and some cool units but they were not cheap. In hindsight we might have been a little wrong but we were just kids that wanted to listen to our music.