Suiseiseki IRL said:
Am I the only one who DIDN'T blow up Megaton.
No, I didn't either. Actually, that's not true; I blew it up on my second playthrough, then felt so bad that I started over.
Anyway, the...er,
experience in Point Lookout (you know what I mean) was one such moment. Stepping out of the Vault for the first time was the other.
EDIT:Oh, I had another. Once, I was walking in the Wastes. I hear a noise and turn around. I'm being followed by a Giant Radscorpion and an Albino Radscorpion, and
they are being followed by 2 Deathclaws. I immediately start sneaking (my logic being that, even if they know I'm there, I'm automatically a lower priority), and the Deathclaws kill the scorpions, but not before the Albino killed one of them. Now, I was using the Chinese Stealth Armor, so by this time I'm hidden. I ended the encounter with a VATS Sneak Attack with The Mauler on the last Deathclaw.