video has a brief informative introduction to "Eroica"; music starts at 06:30 mark
Nearly all of the videos in this section ("30 Greatest Orchestral Works") contain live performance videos. Not this one. For Mahler's 5th, I've chosen an uploaded recording conducted by Rudolf Barshai. Barshai is the conductor whose recording was selected as the best of all the recordings of Mahler's 5th in this analysis and survey by Tony Duggan.
There is an informative Wikipedia entry for "Three Places." It describes how Ives wrote the music to give a feel of being actually at three (actual and specific) locations in New England.
Brief intro by conductor Leonard Slatkin; music begins at 2 min mark
brief intro; music starts at 1:20; NPR has a more expanded commentary on the music, "the most discussed piece of 20th century orchestral music" here
Antonio Vivaldi (1678-1741)
(Franz) Joseph Haydn (1732-1809)
Ludwig van Beethoven (1770-1827)
Felix Mendellsohn (1809-1847)
Johannes Brahms (1833-1897)
Bedřich Smetana (1824-1884)
Johann Sebastian Bach (1685-1750)
Wolfgang Amadeus Mozart (1756-1791)
Franz Schubert (1797-1828)
Robert Schumann (1810-1856)
Pyotyr Ilyich Tchaikovsky (1840-93)
Antonín Dvořák (1841-1904)
Nikolai Rimsky-Korsakov (1844-1908)
Richard Strauss
(1864-1949)
Gustav Mahler
(1860-1911)
Sergei Rachmaninoff
(1873-1943)
Claude Debussy
(1862-1918)
Igor Stravinsky
(1882-1971)
Charles Ives
(1874-1954)
Gustav Holst
(1874-1934)
Aaron Copland
(1900-1990)
Dmitri Shostakovich
(1906-1975)
Image Credits: All images are from Wikipedia entry for the composer, which see for credits and details.