I'm too young (~20) to remember any of the "original" rides, however, I definitely preferred the Swiss Family Treehouse, to the Tarzan copy!!
From all the pictures/video I've seen though, I definitely wish I could have rode the PeopleMover!! It would have been awesome to see the "inside" of Tomorrowland!! I did Rocket Rods when it was around, but it was too fast to take in the sights, too bad Disney won't let you walk the track!!
Also, seeing Tomorrowland as Walt intended it would be amazing. I mean, there's a scale model X-wing above the Starcade that no one gets to see anymore even!!