Favorite 3-chord sequence: the end of the bridge in Elton John’s “All the Girls Love Alice” in Bb minor: Bbb, Cb, Bbmin. Yes, you read that right: B-double-flat, C-flat, B-flat-minor.
Favorite chord: the bizarre blues tone cluster from Billy Joel’s “A Room of Our Own.” G, A, Eb, E with an A in the bass. Weird.
The end of the bridge in “A day in the life,” right before John starts singing again. That Baah ba baah ba ba bit. And of course, the End of “A day in the life.”
Also, the drum solo at the end of “Carry that weight,” Abbey Road, Side two.
Spelled in order that’s B-D#-F#-A#-C#-G# which is a B[sup]maj 13[/sup]
this transcription shows it a bit differently: lucaspickford.com - bass jazz fusion funk transcriptions solos metaphysics physics pickford william burroughs Resources and Information.
Bb-D-F-Ab-C which is Bb [sup]9[/sup]
In Beethoven’s Fifth Symphony, the transition between the end of the third movement and the beginning of the fourth movement. Mysterious playing around in C minor, then G pedal, then the dominant seven chord then…
BLINDING FUCKING C MAJOR!
Another organ choice…the transition @ about 3:45 in Widor’s Toccata, when the 32’ pedals kick in. Sweet.
This was so going to be my wedding recessional at one point (if I could find an organist who could play it).
Chopin’s Funeral March has lots of nice moments.
Likewise Beethoven’s Moonlight Sonata.
Eric Carmen bridged with some Rachmaninoff (beginning at 2:54)
One chord? Yeah, the opening to the Saint-Saëns that Malacandra mentions.
The Beatles/A Day in the Life, if it can be called a chord (the dissonance building @ 1:45 and again at about 4:05), as well as its final chord (4:23-5:04).
It was my wedding recessional.
The start of the Cavalry Charge in the William Tell Overture. 
Good call, a true spine-tingler 
In the opening to The Who’s “Who Are You”, the guitar opens with some high picked notes in a nice melody, then Pete Townsend hits a chord that sounds like a musical sneer. I just love it.
You can hear it at :31 in this video. It’s a chart from Rock Band, but it’s the only video I could find that has the original track on it.
The opening chord for A Hard Day’s Night.
The transition from the talk box solo to the outro solo on “Do You Feel” from Frampton Comes Alive.
The band quiets as Peter plays around the signature melody, D F C D
A quick lick, and he repeats the phrase, building in intensity, Peter let’s out a long “Welllllllll” as the talk box tube slides out of his mouth, big flam on the snare and then…
THE chord. The crowd goes nuts!
It’s just a simple D. Probably open position. Gives me a shiver everytime.
In Synaesthesia, by The Bobs, there’s an arpeggio right at the end of the bridge that gives me chills. (Here starting at 2:35) I’d be curious if any of the more musically inclined dopers could shed some details on that passage.
Since we’re talking classical, Mussorgsky’s Pictures At An Exhibition, the transition from Baba Yaga to The Great Gates of Kiev. In fact, the entiriety of The Great Gates of Kiev, coming at the end of the piece is just a phenomenal musical moment, and the last 8 or so measures are epic.
Me too. Sounds like a train.
The progression of chords at the climax of Barber’s Adagio . . . creating an amazing tension, followed by an equally-amazing release.
In the Beatles’ “The Long and Winding Road,” I’ve always liked the suspended 4 chord in the verse – the one played right over the word “before” in “I’ve seen that road before.” I like the way the melody feels like it’s going to resolve there, then holds up with just that tiny bit of tension, then resolves to the Major V. McCartney is great at manipulating melodies through the use of harmonic tension like that. The guy is a stone genius as a composer. At least he used to be.
Not a chord but…
The two handclaps in Shriekback’s My Spine is the Bassline.
If you know what I mean and know where they are, I guess we can be friends.
Gustav Mahler - Ich Bin Der Weld Abhanden Gekommen
Listen from the beginning…the “moment” is circa 0:31. Whole song is hauntingly beautiful.
Second place goes to Beethoven announcing the arrival of his 9th Symphony roughly 0:29 in.
It’s got to be D Minor:
Nigel Tufnel: It’s part of a trilogy, a musical trilogy I’m working on in D minor which is the saddest of all keys, I find. People weep instantly when they hear it, and I don’t know why.
Marty DiBergi: It’s very nice.
Nigel Tufnel: You know, just simple lines intertwining, you know, very much like - I’m really influenced by Mozart and Bach, and it’s sort of in between those, really. It’s like a Mach piece, really. It’s sort of…
Marty DiBergi: What do you call this?
Nigel Tufnel: Well, this piece is called “Lick My Love Pump”