I still think Phanstasia is the best. I have fond memories of playing it back around 2001 in high school. Completely drew me in. I’ve also played Destiny, Eternia, Abyss, Symphonia and Vesperia. Vesperia would be a second to Phantasia and then Symphonia.
I still love the simplicity of Phantasia’s characters. The characters in the subsequent games became parodies of anime characters.