The proud tradition of opening their concerts with the finale from The Firebird.
The entire final movement of the title track of Close to the Edge. All the parts of the song come together with Jon Anderson's vocals, multi-tracked so it sounds like the entire band is singing...the scale of it is just epic.
Roundabout being used as the ending theme for the first season of the JoJo's Bizarre Adventure anime series, no doubt thanks to the original manga author Hirohiko Araki 's influence (his love for classic rock is prevalent throughout the entire series, judging by character names alone).
Their "trilogy" of prog-rock masterpieces: The Yes Album, Fragile, Close to the Edge, as well as the later Relayer and Going for the One. Some people would add Tales from Topographic Oceans as well.
Chris Squire's solo album Fish Out of Water especially track 1 "Hold Out Your Hand".
If we're throwing in solo albums, Anderson's Olias of Sunhillow certainly belongs on the list.
As does Howe's The Steve Howe Album, especially "Double Rondo", where he plays with a 59-piece orchestra.
90125 counts as well, for fans of their '80's pop-prog style. It arguably was one of the more revolutionary and influential albums of that decade. Even the notoriously prog-skeptic hipster tastemaker Pitchfork praised the album.
While it has its detractors, many fans would argue Drama belongs here as well.
"Endless Dream" from from the sadly-forgotten Talk. Also doubles as a Crowning Moment Of Awesome for Trevor Rabin, who proves here he can write epic songs on the same level as Anderson or Howe.
Union might be widely regarded as a very inconsistent album both in terms of style and quality, but the best tracks on it are fantastic. "Lift Me Up", "Miracle of Life", and "Take the Water to the Mountain" particularly stand out.
"I Would Have Waited Forever" is a pretty good opener.
Minus the odd hip-hop breakdown, "Dangerous" is a surprisingly rocking tune.