Forever Blue to some regions.
I don't believe it's out here in Australia just yet, a local store here had it in and they wont say how, I must say, it really is a beautiful game, pulls you straight in.
I payed a whopping $87 for this apparent (Budget) game, but it is worth it's every dollar.
Definitely not for everyone, but I think more games like this should be made, peaceful games are great, kinda why I love the Harvest Moon series so much.
The graphics are fantastic and the soundtrack is superb, and if you don't like the games in-built tracks it will read for MP3's off your SD card, (Somehow listening to X Japan and Guns N' Roses whilst exploring the ocean doesn't suit) Importing some Enya would work great though.
I was very pleased that you could surface at anytime (not onto the boat, that's a given) I mean as in swim to the surface and have a look around at the islands around you etc etc.
What this game is trying to do is something else, and it does it great, easily at least a 9/10 hands down.