I'm sorry, but the best video game soundtrack still goes to Super Mario Galaxy 2, just like it did 13 hours ago. 

There's really no contraversy. It's practically unanimous. 

This thread should be locked because everyone already knows that SMG2 has the best soundtrack ever. Unless you count Super Smash Bros Brawl. But I don't count it, because it's basically a collection of the best music ever. It's basically completely unfair, so it's disqualified. 

YeayYeah there are many good soundtracks in Baten Kaitos 

I didn't know he did most of the tales games. 

It's close, but I think FFVI wins in my opinion:

The Ys series of RPGs shits all over everything else mentioned in this thread.

Imagine it's 1990.  You're playing your NES, or maybe you just got yourself a brand new Genesis.  Or.. if you're one of the lucky few... you're experiencing these masterpieces make sweet love to your eardrums and rock you like a hurricane for the first time....

Grandia 1&2

How could I forget Grandia?  I love that game, and it's soundtrack.  I haven't played the second, but if it's even half as good as the first, it will have a fantastic soundtrack.

Galaxy 1 > Galaxy 2

1 had Good Egg, Gusty Garden, Battlerock, Buoy Base, Centre of the Universe, Observatory, Melty Molten as standout tracks
2 had Starship Mario, Galaxy Generator and...? Most of the rest is lifted or remixed from Galaxy 1.

The things is that both Galaxy games have amazing soundtracks. I would actually say that Galaxy 1 has the best track out of them (Gusty Garden Galaxy, which still blows me away every time I listen to it), but I'd still go with Galaxy 2 overall, as it has (imo of course) more quality tracks.

Awesome Tracks from Galaxy:

• Overture
• Starbit Festival
• Attack! Bowser's Fleet
• Into the Galaxy
• Good Egg Galaxy*
• Honey Hive Galaxy
• Space Junk Galaxy
• Battlerock Galaxy
• Beach Bowl Galaxy
• Rosalina's Comet Observatory 2
• Gusty Garden Galaxy*
• Rosalina's Comet Observatory 3
• Nemesis King Bowser
• Galaxy Plant
• Battle for a Grand Star
• Birth
• Super Mario Galaxy*
• Blue Sky Atheletics
• To the Gateway
• Ship Plant
• Fight to the Death at Bowser's Fort
• Family

Awesome Tracks from Galaxy 2

• Another Story
• Sky Station Galaxy*
• Starship Mario 1
• Puzzle Plank Galaxy
• Wild Glide Galaxy
• Dash Yoshi
• Silder
• Cloudy Court Galaxy*
• Starship Mario 2
• Honeyhop Galaxy
• Starshine Beach Galaxy (Underwater)
• Bowser's Lava Lair
• World 5
• Haunty Halls Galaxy
• Bowser Jr.'s Fort
• Starship Mario 3
• Melty Monster Galaxy
• Throwback Galaxy*
• Fleet Glide Galaxy
• Time Attack
• World S
• Galaxy Generator
• Almighty King Bowser
• The Fated Final Battle
• Super Mario Galaxy 2*
• The Baby Luma and the Hat
• Green Star
• Theme to Super Mario Galaxy 2

*Best of the best!

You're counting a lot of remixes twice, and for example Throwback is a SM64 remix. Good Egg and Gusty Garden are throughout the Galaxy 2 soundtrack, and the credits music/game themes are almost completely remixes. Reusing level music is incredibly lazy.

Opinion: Many of the songs you've listed for both games are ambient. They work well in game but anyone who can play an instrument can create something like that, it does not take talent. I am judging a soundtrack as if you buy it on its own CD and listen to it, which needs strong themes.

In the end, I just posted the songs I liked (regardless of whether they're remixes or they "do not take talent" to create)... which is how one subjectively chooses which soundtrack one likes the most.

OT: Gotta give a shout out to the Okami soundtrack as well. it's a pretty amazing soundtrack to be honest.