My first FF book was # 65, introducing the Kree and Ronan. Then came the next with Him and I was so hooked. I remember finding the reprint series, Marvel's Collector Item Classics which reprinted earlier FF, and got to see Red Ghost issue which someone has shown the cover. Also the one where Namor kidnapped Sue under the Puppet Master's influence.
I have a vaguer memory of one or more Strange Tales Human Torch vs the Wizard stories from the earlier years. I was hospitalized when I was 8 (1964) and someone gave me those to read, but I don't really remember them very well, other than the Wizard was creepy to me, and the ones that guest starred Sue were also dreamy, sorta eerie (she seemed like a ghost, I guess I wasn't understanding...)