PS1? Vagrant Story or FFIX were always fantastic. Grandia?
If you have access to a PS2 or emulator, I can certainly suggested Drakengard 1, however. I only played it for the first time 2 years ago and was blown away by the experience. The graphics were terrible, the gameplay clunky (though Dragon Riding was fun), but the story.... dear god. Never seen anything like it. Nor has a party of companions ever contained such an assortment of freaks. And the multiple endings, where the first is considered the 'best' ending, and all the ones after that are bad, baddest, badderest and "holy crap flying demonic telepathic cannibalistic babies in the sky" level fucked up. You will never see a weirder, more unique game that'll stick forever in your memory and make you want to tell everyone about what you lived through by the end.