Yesterday Apple released a new EFI firmware update that solves an issue some people had with blank screens on the new MacBook Air.
Here is the information Apple provide about this update:
About MacBook Air EFI Firmware Update 2.0
This update resolves a rare issue where MacBook Air boots or wakes to a black screen or becomes unresponsive. This update is recommended for all 11-inch and 13-inch MacBook Air (late 2010) models.
The MacBook Air EFI Update will update the EFI firmware on your notebook computer. Your computer’s power cord must be connected and plugged into a working power source. When your MacBook Air restarts, a gray screen will appear with a status bar to indicate the progress of the update. It will take several minutes for the update to complete. Do not disturb or shut off the power on your MacBook Air during this update.
Personally I hadn’t experienced this problem with my MacBook Air, but I’m more than happy to install the new firmware to ensure I don’t have it in the future!
Have you been hit with this problem?

I love the fact that Apple can send EFI updates out like that. Imagine trying to get BIOS updates out to the general population?
Why is this even posted on a website supposedly devoted to WHS?
UWHS is a website dedicated to ALL things in the Connected Digital Home – not just WHS. WHS backs up your desktops and computers, and the MacBook Air is something that can be backed up by WHS as well. In fact, before I did the Firmware Update talked about here, I backed up my Air with WHS.