That's an easy call today after Thailand, the epicenter of hard drive production for this planet, suffered severe flooding.
If your PC or laptop is on life support, I would think twice about waiting until Black Friday to replace it.
When the current stock of hard drives is sold out, I'm not going to bet on how quickly it will be replentished. It may be easier to switch to a flash drive (no moving parts) as those can be assembled anywhere qualified to assemble the rest of the machine.http://www.channelregister.co.uk/2011/11/21/thai_flood_prices/http://www.channelregister.co.uk/2011/11/10/goldman_lowers_pc_sales_outlook/
The key driver for Windows 7 has been the motherboard memory speed, the graphics card power. I believe Windows8 will have an easy upgrade path from existing Windows7 machines as the market does not want people to let Win7 boxes pile up while waiting for Win8.http://en.wikipedia.org/wiki/Windows_8#Hardware_requirements
What may put a glitch in this pursuit of more power is the market is now focusing on lower horespower requirements for battery-powered devices (pads/phones) running a different kind of chip from ARM technologies, not Intel.