Nearly all of the first 24 editions of virtually every Marvel series, from The Fantastic Four to Spiderman (including the Amazing Tales in which he was introduced) to Iron
Man, the Hulk, Thor, Sgt. Fury and His Howling
Commandos. Basically all of them.
At a comic book store I was once looking at some collectors editions of those comics priced at about $1500 to $2400. I said to the clerk "Man, I used to have all of these." The clerk, whom I'm sure was Matt Groening's model for Comic Book Man, without even looking up said in a bored voice, "Do you know how many times a day I hear that?"
Worst. Impression. Ever.