I was thinking about best story for each Spider-Man villain the other day. Some villains like Doctor Octopus and Green Goblin, you've got a number of choices whereas Morlun, I'd say just the one.

Here's mine from the comic books starting with:

Green Goblin: The Night Gwen Stacy Died, TASM #121-122. Honourable mention to How Green Was My Goblin/The End of the Green Goblin. TASM #39-40.

Doctor Octopus. A number of choices, I'd go with If This Be My Destiny. TASM #31-33.

Kraven the Hunter. Kraven's Last Hunt and that's where Kraven needed to stay dead.

Morlun. Nothing has come close to Coming Home, TASM (Vol. 2) #30-35.

Venom. TASM #300.

Boomerang, Shocker, the Beetle, Overdrive and Speed Demon. The Superior Foes of Spider-Man #1-17.

You get the idea ; ).