What are some iconic moments in Angband?

[Amnekian]

The only ones that I can think about it:
-Slaying Sauron
-Slaying Morgoth
-Finding the One Ring

What else am I missing?

[Estie]

Slaying Adunaphel and Maeglin tops those 3

[debo]

The Ancient Green Dragon (offscreen) breathes gas. 
*** LOW HITPOINT WARNING ***
You die...

[emulord]

Smeagol stealing, Wormtongue insults you, Finding the Phial, Cracking your character's first vault, "Kavlax the multiheaded breathes gravity", "The nexus Quylthulg teleports you away", "It is a mimic!"

[Jungle_Boy]

"It breathes. You die"

[Derakon]

You see a Longsword (4d5). The Nexus Hound breathes nexus. You sink through the floor.

Of course, these days the damage dice don't leak information that way. I do remember one poor sap who was playing ZAngband and had a level get taken over by one of the nastier breeders. He saw a few "The Power Dragon Scale Mail is undamaged!" messages before he had to flee.

[Timo Pietilä]

You see a Longsword (4d5). The Nexus Hound breathes nexus. You sink through the floor.

Of course, these days the damage dice don't leak information that way.

You see a CGV with Ariel at the middle with only weaklings around it. It walks around crushing everything except BoC. Then at the next block Draebor, the Imp concentrates on your feet, you sink thru the floor.

[Rhonwyn]

I haven't done any of the three you listed yet, but to add to those above, I'd say:
Surviving single-digit hitpoints.
Avenging a previous character.
Successfully sneaking the loot out of a room without waking any of the nasties...

[Derakon]

Surviving single-digit hitpoints.

Oh, yeah. Have you ever survived being at zero HP? It's possible! You only die when you go negative.

[AnonymousHero]

Oh, yeah. Have you ever survived being at zero HP? It's possible! You only die when you go negative.

Not the OP, but, yes. Yes, I have. It was awesome. Obviously doesn't happen very often, but y'know... how awesome would it be if it happened all the time?

[Rhonwyn]

I don't think I have survived 0 hp myself, but I've heard about it.

[Djabanete]

In Hengband, when I was trying to "play faster", I did the Vault quest pretty early (L15? 17?) with a ninja and got blasted to 0 HP before getting out with Sting. It was exciting :-)

[Timo Pietilä]

In Hengband, when I was trying to "play faster", I did the Vault quest pretty early (L15? 17?) with a ninja and got blasted to 0 HP before getting out with Sting. It was exciting :-)

Getting poisoned with plenty of HP and slowly watching HP to go away, get to town and frantically phase-dooring around in hope to get close enough to potion shop to get there before poison kills you and then at zero HP it finally wears off...

I'm not sure which is more exiting, getting single-blasted to zero or that.

[klassik]

how about iconic fails?

the sad realization that the mage you've been playing has already had a spell you were using devices for. at acceptable or better fail rates at that.

[Amnekian]

Slaying Adunaphel and Maeglin tops those 3

Care to elaborate? I killed them and I had trouble with Morgoth and Sauron.