@sinha – great post and a good display of figures. As Sullla mentioned, you should probably include Wii Sports in software sales for Japan since it's not packaged there.
I also noticed that you reversed global hardware sales for the 360 and the Wii. This reversal then contributed to a slightly inflated attach rate for the 360 (3.72 - should be 3.12) and slightly diminished one for the Wii (1.48 - should be 1.77) – Wii actually gets to 1.81 if you add Wii Sports and remove Wii play for Japan. It doesn't change the outcome much (360 still has a great attach rate), but it's more accurate this way