Quite frankly, this is the best RPG I've ever played. I have dozens of RPG's in my collection from NES to PS2, but this one tops them all. I had the Dreamcast version, played just over halfway through, and for whatever reason, i just stopped playing it. That was about a year and a half ago. When i started reading about the Gamecube version, I decided that they had added enough things to give it another shot on a new system.
Probably one of the first things you'll notice from the Dreamcast version is that the random battles have been cut down significantly. That was really my only problem with the Dreamcast one (now that I think about it, maybe that's why I stopped playing it). There is one, maybe two time when you are flying around trying to find something, and you can't avoid enemies at all, but it's never really that frustrating.
The graphics have been cleaned up slightly, but it's not a huge improvement over the Dreamcast one. They are still fantastic though, and there's a few times where your jaw will drop.
They also added a few sidequests. There is a girl named Piastol that you fight several times. She plays a fairly big part in the story. Also there are things called Moonfish. When you catch one, there is a ship floating near your home. Take the Moonfish, feed it to the bird on the ship and he'll grow. The more he grows the happier Maria (the little girl that found him) will be. Then the bird will give you an item. Some of which can be very helpful. There are also other sidequests like Wanted Lists, gathering a crew for your ship, and finding discoveries (over 80!).
The story in this game is fantastic! I've never been so anxious to keep playing an RPG. Games have had great stories before, but usually there's a boring spot somewhere in there. I don't want to ruin anything, so that's all I'll say.
All's I gotta say is that if you have a Gamecube, you HAVE to buy this game. If you don't, then seriously buy the system for this game. If that's too expensive, then get the Dreamcast version. There is no excuse for not playing this game. I haven't been this pleased with an RPG ever! 10/10