comparing the size of the imac and the macbook pro I am quite surprised.
The 2011 macbook pro are 0.95 inch (2.41 cm) thick.
It can include a powerful 7 hours battery, 750gb hard drive, 8gb memory, an i7 processor, camera, wifi, good audio, many ports, nvidia gforce 650m graphic card. And of course a screen panel and the cooling system.
All of it for 4.5 pounds (2.06kg)
On the other hand, behind the screen panel of the 2011 Imac, we can have:
a i7 processor, 1tb hard drive, AMD graphic card, camera, a great audio, many ports, and a cooling system.
It's 1.24 inch thick, 20.5 pounds (9.3 kg), yet it doesnt outstand the specs of the macbook pro (especially the new retina, but to be fair lets not compare new released product with old one)
So I don't think that a better sound system, a bigger screen panel and aluminium case weight 7kg more and double thick. Why is it double thick, and 4 time heavier for similar performances?
The Imac doesn't even include a battery like laptop, so it's even less understandable.