(Keeping this strictly X-related, considering)
I fell in love with Blink back when I read the novelization of the Phalanx Convenant, before I even really knew comics existed. But when I eventually came across back issues of the Age of Apocalypse event, that love was sealed forever. Particularly:
It was such a "FUCK YEAH!" moment.
I do remember, though, back in the old AOL Marvel message board days people accusing Lobdell of creating an "OP character" who shouldn't be able to take on Holocaust solo. Ah, fandom.