Ed Bott from ZD Net investigated the license agreements and reports there will be three different Windows 8 EULAs; one for the retail upgrade (with slight variations for Windows 8 and Windows 8 Pro), an OEM EULA, and a new license type named a Personal User License for System Builder. The latter one is designed for DIY system builders and virtual machines, it replaces the OEM license that is typically used by consumers who build their own PC but the exact cost of this new license is still unknown.
The downside of the new EULAs is that there's no longer a grace period. Windows 7 gives the user 30 days to activate it with a key, after which the user can rearm it another three times, for a total grace period of 120 days. This enables you to make significant changes to your system (such as a new motherboard) before activating Windows 7. This stops with Windows 8, the product key needs to be entered during setup and is immediately activated.
All this valuable convenience stops dead with Windows 8. Microsoft has gone back to the dark days of Windows XP, where the product key had to be entered during setup, or it would be stopped dead in its tracks. This activation behaviour could be seen in the preview versions of Windows 8 (which were supplied with the same activation key for everybody). However, this behaviour has now been confirmed to also be in the release version of Windows 8, by MSDN and TechNet subscribers, who have official access to the final retail copy. In fact, the very latest version of Windows XP actually allowed delayed activations, so it's hard to understand why they had such an unhelpful change of heart.