Off the top of my head...
I'd add (Peter Parker:) Spider-Man #75 -- It reads well, and it's important in that it sets up so many things that are a part of the "modern" Spider-Man. And it has a lot of the answers to past questions.
I'd also add Ultimate Spider-Man #13 -- where Peter reveals to MJ that he's Spider-Man. So cool; I reread it at least once a year.
I'll post more later,