I'm not being offered SP1 and neither were two HP PCs I was running updates on earlier today. I wonder whether they are spreading the load on the download servers by not offering it to everyone at once?

Something that I've never noticed the likes of beforehand, perhaps this is relevant...

Quote:
Things to know before you download Windows Vista SP1

Windows Update will recognize PCs with known problematic drivers and postpone downloading Windows Vista SP1 until the PC has updated drivers or other applicable updates. Using Windows Update will help ensure you have the most trouble-free update experience possible.

Some Windows Vista users may encounter an issue with a small set of hardware devices that may not function properly after updating a Windows Vista PC to Windows Vista SP1. This is an issue with the way the device drivers were re-installed during the Windows Vista SP1 update process, not with the drivers themselves—these drivers worked on Windows Vista RTM and they work on Windows Vista SP1. This problem is typically corrected by simply uninstalling and reinstalling the driver. We are working with the manufacturers of these devices to get the known problematic drivers and their install programs updated, and also on other solutions we can use to ensure a smooth customer experience when updating to Windows Vista SP1 using Windows Update. For new PCs provisioned with Windows Vista SP1, this is not an issue.