Back in the 1970's, every boy had a G.I. Joe, and possibly more than one. It was as much of a doll as a Barbi was, but they were MAN dolls doing MAN things. Girls couldn't possibly understand. (Unless you got stuck playing Barbi, then you used your own doll and NEVER Ken.)
In many ways, I am utterly at a loss to talk about G.I. Joe beyond that because that play was so ubiquitous. There was no story attached to him, or TV, or anything like that. He just was. I had this red haired G.I. Joe. First I shave his beard, and then I eventually shaved him bald. Why? I guess that he looked better that way.
I used to take the head off of my doll, because the head attached to the neck ball joint and was removable. It was just a soft rubber that gripped on. The head itself was hollow and squishy. You could drop these guys on their heads forever and they'd never notice. Eventually, after enough abuse, the elastic that held the doll together snapped, leaving my Joe a limp rag doll. Thankfully, mom had mercy on me and bought me another.
My brother had an AT-II Mobile Support Vehicle, which was the multi-part yellow vehicle, which could drive like a big camper, or split apart into smaller components. It featured a wind-up propeller that shut up from the rear camper. That was the satellite that you were supposed to track. The front connected to the rear with a simple plastic pin over a hitch. The back opened up into a technical area so that you could do techno-stuff. (We didn't use that word back then. If we had only known it, we would have used it.)
I had a green footlocker for my Joe and all his gear, along with some diving equipment (Deep Sea Diver set). He had one of those big helmeted diving suits. Some friend must have had the six-wheeler, because that looked familiar to me. The teenager across the street had a space capsule from the 60's which he gave away to us. I don't remember who got that prize.
My aunt made clothes for Barbies, and every time that she asked what I wanted, I requested a G.I. Joe Parachute. My poor aunt had no idea how to make such a thing. Even worse, she didn't give me something good enough to make me happy, because it's not like a parachute is that hard. It's s a circle with strings tied to a vest. Done. It can be crappy, it was for a boy who intended to throw his doll up into the air.
Over the years I did attempt to make some parachutes. None of them worked well, but I had fun testing them.
G.I. Joe wasn't the only doll on the block. In the early 70's, there was also Big Jim. Jim was an outdoorsy guy, and he was BIG, and his name was JIM. He had a camper and he could wear all of G.I. Joe's clothes. That's about all that really mattered. To be honest, I had no idea what Big Jim connected into, if he even connected into anything. All that I had for Big Jim was his camper. I figure that I got Big Jim somewhere before Hurricane Agnes (1972), because I remember pushing his camper around the dining room table, chasing my sister. So I must have gotten Big Jim when I was five, in 1971. In the end, Big Jim didn't make much of an impression upon me, but his camper did.
Another doll that I played with was the Six Million Dollar Man, Steve Austin. With the show starting in 1973, and merchandising coming soon after that, you can bet lots of boys had a Steve Austin. I certainly did. He had interchangeable arms, and the arms had flesh that rolled up to reveal his bionic workings. You couldn't get cooler than that. A friend of mine had a bullet man, which I think went with that toy line, but I could be so wrong.
Even cooler, Steven came in this capsule thingie which always did what you needed it to do. It sealed him and all his stuff up into one neat little container. I think that I only had the doll and the repair station as none of the other toys rings any bells.
The younger kid next door never had many big dolls, but he did have many super-hero action figures. I didn't know the marvel heroes back then, but he had them.