Wii does not have the highest attach rate. 360 does.

There is some truth in this. It becomes even more irrelevant when taking the Wii's massive userbase into consideration.

Somehow that has not stopped the rampant damage control in this thread.

Well, here's the VGC SW for 2008.

Wii: 171.04M

Ps3: 79.14M

X360: 111.5M

So, if VGC was to be correct, the average units owned would be (for the AR to be equal)

Ps3 = 1

X360 =  1.4

Wii = 2.16

X360/Wii ratio: 1.56

Now, let's check this (just quickly, I'm not gonna bother doing it thoroughly)

Start of the year.

Ps3 = 1

X360 =  1.748

Wii = 2.12

X360/Wii ratio: 1.21

End of the year

Ps3 = 1

X360 = 1.39

Wii = 2.26

X360/Wii ratio = 1.61

Then claim that 50% of the total sold were in 2008 (it's roughly 50% for Ps3, 60% for Wii, 40% for X360), and you get

Ps3 = 1

X360 = 1.57

Wii = 2.19

X360/Wii ratio = 1.41

Now, the SW ratio again

Ps3 = 1

X360 =  1.4 = lower, would mean that X360 AR is smaller than the Ps3 AR in 2008.

Wii = 2.16 = The same, would mean Ps3 vs Wii ratio is pretty much identical in 2008.

X360/Wii ratio: 1.56 = Higher, would mean Wii ratio is higher than the X360 AR in 2008.

This isn't meant to be completely exact (heck, the way I'm doing it may give a very flawed result), and I'm not really trying to make a point (rather check the data).

Edit: I'm including Wii Sports.