Oh man, so difficult! I mean, the Kingdom Hearts games are overwrought and kinda hokey IMO, but doggone it if I don't absolutely adore Simple & Clean. And I fell in love with Still Alive (from Mirror's Edge, tho the Portal song is awesome in a completely different way) the first time I heard it. And what about Wind's Nocturne from the PS1 Lunar? I wasn't the biggest fan of how Working Designs handled their localizations, but they knocked it out of the park with that song.
But you said one, one that I consider the best, so I'll hold to that - here it is: