Well, I personally think September is more likely, as I could see the two systems intersecting at about 13.5 million units in that month... But we should stop predicting when Wii catches 360 until we know Nintendo's shipment goals.
"[Our former customers] are unable to find software which they WANT to play."
"The way to solve this problem lies in how to communicate what kind of games [they CAN play]."
Satoru Iwata, Nintendo President. Only slightly paraphrased.