Fantastic Four #51, “This Man, This Monster” by Stan Lee and Jack Kirby
Master of Kung Fu #29, “The Crystal Connection”, by Doug Moench and Paul Gulacy
Daredevil #191, “Roulette”, by Frank Miller
And currently… Well, I thought of saying The Incredible Hulk #603, in which Daaken, son of Wolverine, meets Skaar, son of the Hulk. Or the issue of x-Men Prelude to Schism in which Emma Frost was ready to leave Scott Summers, until they each confessed the secrets and lies between them. Or the issue of Iron Man in which Tony Stark shut down his own brain.
Instead, I’ll going to say Thor #619, a chapter of the story “The World Eaters”, in which Loki came back to the Asgardians.