The PS3 has a much bigger sales potential than the 360.
The PS3 has a better lineup for this holiday season.
The PS3 will have a better online for FREE with Home this year.
The PS3 has a better brand name.
The PS3 has a better hardware reliability reputation.
That leaves the 360 with a price advantage. Last gen a console called the Gamecube had a price advantage and it didn't even get to second place.