My Dyno Comp ii. I'd ride the S out of it. My parents had it for years in storage. I gave my blessing 20 years or so ago to get rid of it. So stupid. These things in this condition are worth thousands today. Edit: The photo isn't my bike, but it was identical and in near mint shape since I really only road it for transortation as an 11 year old.
The other, which I can actually get now, would be my Kyosho Ultima RC buggy. Kyosho has re-released their 'classics' made with modern materials so I can still scratch that itch.