Star Wars (the original movie, whatever number that is) by John Williams, the theme and the Imperial March Darth Vader’s theme and the Cantina song.
Jurrasick Park by John Williams is also pretty phenomenal especially the theme
Not really a soundtrack, but I love the Star Trek themes from the Original Series Movie, TNG, Deep Space Nine and Voyager.
The sound track for the John Adams miniseries (starring Paul Giamatti), especially the theme
And the East of Eden theme song by Lee Holdridge which you can hear in this lovely performance by Michelle Kwan
The theme for Legends of the Fall
The theme for Memoirs of a Geisha perfomed by Yo-yo ma.
The original theme music from the TV series Monk by Jeff Beal as well as the newer theme song by Randy Newman and the last song from the series also by Randy Newman
And for those of you who might recall this nifty show from the early 80’s the theme song from the TV show The Day’s and Nights of Molly Dodd