I vote for the extremely underrated and forgotten arrangement of "Under the Stars" from Final Fantasy Tactics: The War of the Lions for PSP. http://www.youtube.com/watch?v=2ax4BRsVBTk
The piano is so relaxing and then at the 2:00 minute mark it really picks up and becomes something very special, IMO. I used to watch that cutscene over and over just for that song as well as the fantastic voice acting.
This is the scene that it originally played in: http://www.youtube.com/watch?v=OPyRgkWnemw
Other great ones include "To Zanarkand" (as much as I hate FFX), "Keeping The Peace" (Dissidia), "Cerobi Steppe" (FFXII), "With Pride" (Crisis Core), and of course Aerith's Theme.
Vayne Solidor of the DD012FF Board Currently playing: Majora's Mask (again), FFVIII, Vagrant Story (again)