From the NPD analysis at Gamasutra here there are three points of note in regards to the state of the sales of X360 vs PS3.

(i)

From Gamasutra -

"the Xbox 360 was only up from 4.6 million units during calendar year 2007 to 4.7 million during 2008. Without the dramatic increase in sales after Microsoft's August 2008 price drops, the system might well have recorded lower sales in 2008 than in 2007."

It shows another reason why the X360s price drop occurred. It was the only way to boost sales over 2007 levels. Even then, it only just squeaked in. The response in the press and markets to MS losing YOY sales in its fortress would have been very damaging, especially in the face of PS3 and Wii increases.

(ii)

US Software sales in 2008 per system. This is calculated by unit software sales in 2008 / total install base in Dec. According to Gamasutra in 2008, the Wii sold estimated 70 mill units of software, X360 sold around 49 mill units of software and PS3 around 27 mill units. Using install bases as of Dec of Wii 17.6m, X360 13.8m, PS3 6.9m:

Wii - 3.97 games / system

PS3 - 3.91 games / system

X360 -3.55 games / system

(iii)

Nintendo is competing with Sony and MS no matter what the respective chiefs say. The 5% market drops of Sony and MS have gone directly to Nintendo. That is a huge chunk

America has a over 10 attach rate for the 360 so i call those numbers bogus simply because that would mean a drop of 6.5, not very likely, plus it would also mean 2008 was the 360's lowest selling software year which again is bogus as we know it was their best year. So the numbers don't quite add up.

This is not attach rate. Attach rate is number of software units sold per hardware unit sold in a given timeframe.

These figures measure total sales rate of the userbase over the year. ie, how many games sold per X360 user in 2008 in US is 3.54. Most surprising of all - per system, the Wii sells more software in 2008 per user.

What does this mean? It shows relatively how much of that user base does not buy software. If the attach rate is high, but userbase sales is low, it shows:

(a) large amounts of userbase do not buy software or

(b) Large numbers of failures not replaced by the userbase

This is the most important figure a 3rd party developer will look at. This is why 3rd party support for the PS3 is not going anywhere. It also explains the huge volume of titles being released on the Wii.

ps3 wasn't hacked yet piracy may be reason too.
but sony system are still software sellers it seems.

and games like wii fit , require an accesory to play it.

"(Remember that Nintendo's marketshare includes Wii, DS, and trace amounts of Game Boy Advance, Sony's includes PS2, PS3, and PSP, and Microsoft's includes Xbox 360 and trace amounts of Xbox):"

This makes more sense.  I did not realize they were counting everything for Sony.