Your ultimate goose bumps moments in prog?

Fripp's solo on The Night Watch - S&BB

The Mellotron on PFM's - The World Became the World

Julie With... by Brian Eno
Two Hands - King crimson (Guitar solo)
Sample and Hold - Bill Bruford
The Solo parts of Sound Chaser by Yes
Nevermore - UK

Yesterday I was carried away by the first part of Solaris their debut album Martian Chronicles, great synthesizer work and splendid, very exciting build-up

Dirk, I am sure you will find some new ultimate goose bumps on the new Mostly Autumn album, check it out

Indeed Jalas, the first part of Trilogy with the sparkling piano work, halfway blended with the fat Moog synthesizer flights...............goose bumps!

A recent one is Tool's 10.000 days, the part where Maynard cries "It's tiome now, give me my, give me my wings!"

VDGG's Still life has at LEAST 10 as well (frightened in the SILENCE...), and Mars volta (who brought me here...) And then Marillion has just too many to be counted..

3:07 of "You'll Be in my Heart"

TO FLOYDOID:
Your pictorial sign off above is doing it to me right now.

Let's see:

There's quite a number of ones I can think of--here's the biggest ones for me:

Yes
Siberian Khatru, around the 5:30 mark, when Jon Anderson begins the single-word chanting part.  The part that really gets me is Bruford's snare rolls here, against the otherwise rather calm texture. 

The Gates of Delirium, around the 8:00 mark when the "battle" sequence begins, all the way through the end of "Soon".

ELP
Tarkus, the Eruption section

King Crimson
Epitaph--The last 2 minutes, mainly because of the mellotron and timpani

Larks' Tongues In Aspic, Part Two--The whole thing.

Radiohead
In Limbo--The whole song.  It's Jonny Greenwood's little riff that really gives me goosebumps. 

Dün
Arrakis--The point where it picks up tempo wise.

And I concur with the two posts preceding regarding Floydoid's sig.

-Topographic

... The build up and climax toward the end of Echoes, and any solo in it for that matter. Makes me want to cry.
... Repeatative echo of "Stones" on Animals
... Main melody of Crimson King
... In the Flesh
... "I get up, I get down" build up to organs, and then the organs on Close to the Edge
... "Tell the moon, don't tell the marcher" reprise after Heart of the Sunrise, and Heart of the Sunrise for that matter.
... When Lake exchanges lines with the computers in the third impression of Karn Evil 9:

"I am all there is."
"Negative! Primitive! Limited! I let you live!"
"But I gave you life!"
"What else could you do?"
"To do what is right."
"I'm perfect! Are you?"