the Bolero love is warranted. nobody was ever so productive as one who was listening to Bolero.
my favorite piece is from the Romantic period, from Smetana's
My Country (how cliche romantic period is that?

), The Moldau. It's just increds and it traces the entire life of the Vltava river, from its small spring source through the countryside and through Prague and on a wild fox chase and eventually disappearing by merging with the Elbe.
You can imagine my delight when I heard it played prominently in The Tree of Life.
anyway some other faves:
Rach III has been mentioned, as well as Shine. if you haven't seen it, you need to go see the old pirate as the eccentric pianist genius hermit guy
Beethoven Violin Concerto in Dmaj
try to listen to Brahms' A German Requiem and not just weep uncontrollably
I know the Blue Danube Waltz by Strauss is overly familiar, but the entire 10 minute piece is fantastic