Xbox360 selling quicker than the original Xbox
A quick comparison of sales from launch shows that in two years from launch Xbox360 managed to sell 14.1 million units compared to 10.9 million for the original Xbox.
http://digg.com/xbox/Xbox360_selling_quicker_than_the_original_Xbox
http://vgchartz.com/hwlaunch.php?cons1=XB®1=All&cons2=PS3®2=All&cons3=X360®3=All&weeks=156