One of my single biggest fears after the initial reveal of 3D World was the music.  Galaxy had epic music.  The initial trailer had very lame backing music.  But 3D World will have a soundtrack just like the Galaxy games, with epic orchestration well suited to the various levels.  What a relief!

As shown in IGN's gameplay videos:

http://ca.ign.com/articles/2013/10/01/5-unexpected-joys-of-super-mario-3d-world

YES! The music from Super Mario Galaxy was excellent! Like the Final boss fight in Super Mario Galaxy 2 with Bowser!

I am pretty sure it will reuse Mario3DLand music. The trailer used some of 3DLand music. NSMB also used the same music for 4 games (which is really lazy and sad imho) but at least 3dLand got a few new tracks.

One of the coolest things in Mario games was that they always built new music and if not new music they made old melodies sound fresh.

NSMB had boring and repetitive music and I hope we will never see that again

This'll be the first Kondo actually composes music for a game since Skyward Sword 

http://en.wikipedia.org/wiki/Koji_Kondo

I don't know if it is using anything from 3DLand, but it sounds new to me and the soundtrack to the Bowser level sound outstanding and fully orchestrated.  Some of the other levels sound unique, with some of it having an excellent jazz feel.

You could say that I'm pessimistic or outmoded but I would have prefered Koji Kondo. He's so talented !

The music is these gameplay sessions is not fantastic at all, and  for what I see, it's worse (understand less good) than in SMB3, SMW, SM64 or Galaxy soundtracks.

But I may be mistaken.

The only one that sounded unique was the "Power-Up Bonanza" video, the rest were meh.

The music in the last trailer was incredible.

Sounds good to me. But of course, Nintendo has ALWAYS been consistent at providing top-notch music and music-production for the 3D Mario games. It's just the sad, lazy NSMB series where ALL 4 games literally used the DS soundtrack where they've consistently dropped the ball. I will NEVER buy another game with "BAH!...Bah!-Bah!" in the soundtrack. Consider yourselves warned, Nintendo.

The Mario Galaxy games have two of the greatest soundtracks in the medium, so I'm not expecting 3D World to live up to that.

That said, like the gameplay and graphics, the music looks much more interesting in the newer footage, and Koji Kondo composing is awesome news, his soundtracks are amazing.

Oh, and I second the NSMB series having vomit-worthy music. That "bah bah" shit is insufferable.