I have read a lot of spidey, most of the best stories were out in Amazing.
I have about 250 issues of Amazing, ranging from #250 to 550.
Spectacular I think of have 180 of the 220 issue run.
I have all of Web, which was about 100 issues
And most of Spiderman, which was around 90 I think.
There were a bunch of newer titles also, like Friendly Neighborhood Spidey and Sensational Spiderman.
At one point in the 90s they had all four titles running and the story arcs spanned them all, so you had to buy them all if you wanted to read it. I was in university at the time and not collecting, I picked up most of the issues from that span a few years ago.
I stopped collecting again last year, mostly because I was spending about $150 a month. There are many good storylines but that is just to much to justify on a comic book hobby. They also rebooted Spidey in the books a few years ago with One More Day and I wasnt a fan of that storyline or the new direction.
The Grim Hunt syory arc from about two years ago was good and you don't need to know anything recent to read it. You should be familiar with Kraven's Last Hunt though. I think these were the first spidey books I bought as a kid.