I think most vocal XBox 360 fans misunderstand how attach rates work, but I also think they would rapidly learn how it works if the PS3 had a headstart on the market.

Anyway total attach ratio at this point:

PS3 8.1
XBox 360 (due to its headstart, a little higher) 8.8
Wii 7.7
PS2 10.3

I have updated the OP with the following:

"My assesment was correct. For the last reported fiscal year the PS3 sold 115.6 million units software units and the XBox 360 sold 103.1 million units. This while at the end of March 2010 Sony sold 4.47 fewer units to retail than the amount of XBox 360s shipped by Microsoft.

Meanwhile VGChartz has also already adjusted the PS3 install base up in Europe/others for the period before 2009."

one question.... where the 353m games come from? official MS numbers? any link?

Well over 1,000,000 copies of MW2 for 360 were pirated in 2009 alone.  That was well over 20% of the sales at that time.  Not sure what the most recent figures are but most of the games on 360 get pirated by quite a large percent.

Please don't post three times in a row in your own thread Mike, it is spam and makes it look like you are bumping your own thread which is not allowed.

@ Torillian

LOL with 3 minutes apart?

I'm just telling you how it looks, take it as you will.

On Jan 02, 2010 WW chart the diff. was exactly 2.0. 8.56 xbox, 6.56 PS3 so they have gained .12. Not a huge change but a positive. Why I'm arguing the PS case I'm not sure. Yes, there were big games released but the slim effect will continue and the trend will not stop until Reach imo. I hope Wake and better nos for the 360 on Red Dead and PoP: FS might make a difference this month but the pre-order charts say otherwise.

We'll see what natal and the holidays bring. I'm interested to see if multi-p versions of Vegas, Crysis 2 etc, post similar nos.

Call me stupid, but I'm not really seeing how the 360's one year head start fudges with the attach ratio.
If anything's a factor, it's not that the 360 had an extra year, it's that the price of the PS3 was waaay high. Sony's biggest mistake might have been putting the cell processor in that thing; we haven't even really seen many benefits from the processor manifest itself in actual gameplay. (sorry about going off-topic)
I'd think that If people really wanted the PS3 that badly, they would have bought it regardless of the 360 releasing first...Howerer, the price was so high that they had to wait for it to drop.
Which is why the slim sold so many units when it came out.
And now the PS3 is catching up quickly, Sony's turning a profit, etc, etc.
I was about to use the wii as an example, but I'm not so sure the Wii's overall software attach rate is as high as its two competitors