Good choices Jon! I would drop ASM 10 and replace it with ASM 39 and 40.
1. Kraven's Last Hunt, Who says copper age books suck?
2. ASM 121-122, I can only imagine what it would have been like to buy 121 off the newstands. Why couldn't they have killed someone else?
3. ASM 39-40, I can't believe this was the beginning of Romita's run.
4. ASM 30-33, These were the first Ditko back issues I picked up. After I read them, I was hooked.
5. ASM 17-19, I couldn't say it any better Jon.
Honourable mentions go to ASM 50 and the whole Ned Leeds/Rose/Hobgoblin/Gangwar storyline.