I think the iPad might kill the PC.
First quarter of iPad sales in 2010 - 3 million sold.
Last quarter of iPad sales in 2011 - 15 million sold.
First off, the iPad killed the Windows netbook market completely and now it's starting to kill the low-end desktop market as well. I predict that how ever many additional iPads get sold this quarter directly reduces the amount of Windows PCs sold. It will be a direct cause and effect from this point on. If Apple has a 40-50 million iPad 3/iPad 2 quarter April to June, that will signal the beginning of the end for Microsoft/HP/Dell.