Yeah, I think it's all about nostalgia and often combined with the "wow" factor it gave us when we first used it...
My first computer was the Vic-20 and I remember it very fondly, along with the C64 and then the Amiga. I love all three machines, although arguably these days they are no more than toys from the past.
It's the same reason people love old cars (their first drive, etc) and music from their teens - I love early Duran-Duran, for example, although I generally don't go around boasting about the fact! :-)
It all brings back the "feel-good" factor from when our lives were simpler and more youthful!
It'll be the same (in the future) for those kids who grew up the the Playstation or N64... Or Subaru WRX... Or The Spice Girls!
Cheers,
Mike.