My first ever issue of Captain America (and the Falcon) was #206 by Jack Kirby, and it's always stuck with me something fierce. It figures in my waking nightmares!
The villain of the piece is a banana republic dictator called Hector Santiago, AKA the Swine, who celebrates his birthday by having starving prisoners/slaves to share his feast. Sounds like a nice guy, right?
One sadistic villain that definitely deserved his death - being ripped in half by a Kirby mutation - two issues later. And then Arnim Zola showed up. VERY memorable comics.