Should you wait for it? In a word - NO. The security and easy of use benefits of Windows Vista make it worth upgrading as soon as possible. As Steve mentions there are those (perhaps you) who simply won't install a new operating system until it reaches Service Pack 1. I'm not claiming Vista RTM was perfect but assuming you have a machine with reliable drivers then my experience has been very good indeed.
I understand that upgrading large estates of machines is not a trivial matter and that device driver support and application compatibility are key considerations.
The news on device driver (from the white paper) support is good too:
"Microsoft has added 700,000 new device types since the initial Windows Vista release in November 2006. Including device drivers in the box and those available from Windows Update, by July 2007 Windows Vista supported nearly 2.2 million devices. That covers the vast majority of devices in use. The number of Windows Vista logo devices exceeds 10,000, and the growth is outpacing Windows XP"
Service Pack 1 doesn't bring major new features though it does increase the granularity of existing functionality and of course there are bug fixes in there too.
The whitepaper includes a link to Jeff Jones' Windows Vista 6-month vulnerability report which shows that "Windows Vista had fewer security issues than all the popular operating systems he studied".
I think the following paragraph (from the white paper) sums up the deployment stance of many mainstream organisations:
"Although most companies are cautious when deploying a new operating system, many have already started testing and evaluating Windows Vista for deployment, and some have already deployed Windows Vista into their production environments and begun seeing the business benefits Windows Vista can provide."
Application compatibility has of course been a concern for those considering moving up to Vista on a large scale. It's great to hear that the application compatibility team have worked with Independant Software Vendors (ISVs) to make life as easy as possible for them and have reported that "nearly 2,100 applications now have the Windows Vista logo".
Here's a summary of what's in Service Pack 1 courtesy of the white paper:
"The updates in Windows Vista SP1 fall into three categories, which the following sections describe in detail:
- Quality improvements, including all previously released updates, which address reliability, security, and performance.
- Improvements to the administration experience, including BitLockerTM Drive Encryption (BDE).
- Support for emerging hardware and standards, such as an Extensible Firmware Interface (EFI) and an Extended File Allocation Table (exFAT)."