Ar Tonelico is full of amazing music (I mean, come on, music is kind of its thing), but this is my favorite song. I have listened to it so many times. Just wish it were up in better quality. :B
Also, I figured this might be the best place to ask: anyone know artists who compose good, original JRPG-style music? The only one coming to mind is Seiko-P. I'd love to know more artists who can really capture the vibe (I'm not sure what else to call it, haha) while still doing their own things. Bonus points if it's not solely chiptune (not that there's anything wrong with chiptune! it is just so easy to find I'm tripping over it).