I assume you know Microsoft released Windows 8 Developer Preview.
1) The UserAssist registry keys still exist, and still use ROT13 encoding:
Notice that there are also entries for the launching of Metro apps (e.g. alarms).
But there are also a couple of extra keys, I’ll analyze them when more definitive versions of Windows 8 are released:
2) My USBVirusScan tool still works.
3) The AppInit_DLLs registry key still exists:
4) And the SafeBoot keys also still exists, but Safe Mode (F8) has a Metro-style GUI.