Although I'm not as old, I got my first TF, for christmas, back in '05. I watched only G1 back then (boomerang reruns) and I really wanted a G1 Optimus Prime, so I asked for op for Christmas.
But, as you know, it wasn't the 80s anymore and Cybertron was out, so I got the Cybertron Optimus Prime figure (still have) which was awesome (couldn't tell the difference) from santa and I cherished and still cherish that toy.
At first, I thought, like g1 optimus, that the legs went backwards, until I read the instructions.
I still have Prime and he is one of my favourites in my collection, not just because it was my first TF, but it is also very G1-esque. It is currently kind of my Classicsverse Optimus at this point. (not entirely though- in my UT display)
It also kept my love for tfs alive, by getting me into the Cybertron cartoon.
Good times, good times...