Valkyrie Profile is definatly one of my favorites, I own all 3 games. However it's not for everyone. Maybe I only liked the art because as a sprite artist I thought it was impressive and beutifull. The story is good but there isn't much story telling, and it's a littl weird. I'm also huge on Norse Mythology (though I don't like alot that they changed.)
Anyway if your looking for good RPG Gameplay with tons of challenging battles, that's one way to go. MC DUI has good recomendations.
I'm looking forward to the Disgaea and FFT ports.
Crisis Core will probly be good for most people. I hate the looks of the battle system though.
Other than that, there's alot of mediocre titles you can pick up, I like to play them sometimes. Games like The Legend of Heroes series. It's not great. But it's kinda fun when your in the mood for a really old school feeling rpg.