For epic moments, I'm going to suggest a strong but quiet image.
The 1st page of issue #200. The doctor tells Tony that his friend is dead and Stark's only reply is "I know." The stance, the look on his face, his choice of words, they all depict a man who has come to grips with what must be done. He doesn't want to be Iron Man anymore, hell he was afraid of being Iron Man but none of that mattered anymore. He knows now that Stane must be stopped and that he is the only man that can do it. Notice in the following pages with Cly and Rhodey that Tony never has to be convinced to put on the armor again. His mind is made up already.
Like I said, quiet but that panel has a lot of power. Plus it sets up one of the greatest and most iconic IM fights ever.
Typhon, I know this is a really late follow-up (I didn't notice this thread until now), but I completely agree with everything you wrote. Beautifully said.