Final Fantasy X
The first game in the series to be released on the Playstation 2, Final Fantasy X was the last (offline) game in the main series to be made before Square's merger with Enix, after which it is commonly agreed that the franchise began to go downhill quality-wise. Featuring voice acting and graphics that were nothing short of spectacular at the time, the game focuses on Tidus, a young man who is sent one thousand years into the past, after which he becomes part of a woman named Yuna's quest to rid the world of a menace called Sin. Naturally, though, everything is not as it first seems... For the first time, Nobuo Uematsu was not solely responsible for the game's score, sharing composition duties with Masashi Hamauzu and Junya Nakano. Despite their efforts, however, it is Uematsu's works that dominate this top five.
To Zanarkand One of the most well-known tracks in the entire series, and for good reason. This beautiful melody encapsulates the bittersweet nature of Tidus' ill-fated story perfectly, and words cannot do it justice. http://www.youtube.com/watch?v=h-0G_FI61a8
Ending Theme Tidus' story is bittersweet purely for the fact that although he helps Yuna and company defeat Sin, it comes at the cost of his existence, separating him from the woman he has grown to love. This piece, which plays after his disappearance, conveys the sadness of this in wonderful fashion. http://www.youtube.com/watch?v=3bv1oNp_wJw
A Fleeting Dream Otherwise known as 'Someday The Dream Will End', this is another track that conveys the bittersweet nature of the game's story, though it incorporates uplifting melodies as well as melancholic ones. http://www.youtube.com/watch?v=miuNmfcBfu8
Original Sin Criminally, this track is not actually in the game itself, and can only be found on the soundtrack CD. It is similar to the game's final battle theme, though vastly superior, and would've been a great accompaniment given its trance-like feel. http://www.youtube.com/watch?v=d_Pzo6p5SY8
Seymour's Theme Joining Kuja in this list of underappreciated villains from the series is Seymour, who makes up for his ridiculous looks with subtle cunning and deviousness. This track hints at his dark nature, but doesn't give everything away prematurely and is all the better for it. http://www.youtube.com/watch?v=NQbXYN4-vPk