Latest SoundScan figures from Billboard's October 13, 2007 issue (sales through September 23, 2007):
Unison - 1,216,000
Celine Dion - 2,336,000
The Colour Of My Love - 4,492,000
Falling Into You - 10,765,000
Let's Talk About Love - 9,436,000
These Are Special Times - 4,837,000
All The Way...A Decade Of Song - 7,504,000
The Collector's Series Volume One - 889,000
A New Day Has Come - 3,279,000
One Heart - 1,775,000
A New Day...Live In Las Vegas - 485,000
Miracle - 922,000
Now, if we compare these numbers with the last ones we had from the end of January 2007, we can see that after 8 months she has sold:
Unison - 0 copies
Celine Dion - 1,000 copies
The Colour Of My Love - 5,000 copies
Falling Into You - 11,000 copies
Let's Talk About Love - 10,000 copies
These Are Special Times - 1,000 copies
All The Way...A Decade Of Song - 87,000 copies!!!
The Collector's Series Volume One - 9,000 copies
A New Day Has Come - 15,000 copies
One Heart - 6,000 copies
A New Day...Live In Las Vegas - 13,000 copies
Miracle - 13,000 copies
However, the list published in the Billboard magazine isn't complete:
1) it doesn't include French albums;
2) it doesn't include Unison/Celine Dion/The Colour Of My Love 3-CD, which is counted separately by SoundScan (22,000 copies sold till January 2007);
3) it doesn't include CD+DVD version of Miracle, which is also counted separately (65,000 copies sold till January 2007).
P.S. And I think that All The Way...A Decade Of Song stops people from buying her earlier albums.