I am not sure why apple needs to sue they are already selling as many as they can produce at the moment. Microsoft suing I can understand as they have been pushed out of the market so need to find ways to make money of it as well as force manufacturers to produce
and sell W7 devices.
Apple are staying ahead in the hardware by bringing latest stuff in the market first and then getting steeper discounts then its competitors over the life of the hardware. As they gain more market share in the desktop I expect them to do this for more for desktops and laptops which should accelerate its Desktop Market share as well.