Wow, you consider all of these to be more important/impactful to the Silver Age than ASM #1???
Yeah, that's a bold statement. I can't see Avengers 1 as having more of an impact as Spidey 1. Which brought us the Bugle, JJJ, The Chameleon and Spidey in his own title. All the others there can be an argument for I guess. But that's just my opinion.
I'd have to put ASM1 somewhere between 4 & 7. Spider-man is just a much bigger character than any of the others that the first issue in his own title has to be up there. Someone else mentioned that a good analogy is in the GA where Superman 1 and Batman 1 are considered the 3rd and 4th most valuable books behind only Action 1 and Tec 27. Big "first" appearances lag like Marvel 1, Cap 1, and All-American 16. While the gap between Spidey and the Hulk may not be as wide as say Batman and the Green Lantern, there is no question that Spidey is king.