I just recevied an updated paper from Microsoft regarding Windows Vista and some statements why not to wait for Windows7.
There is no need to wait for Windows 7. It is a goal of the Windows 7 release to minimize application compatibility for customers who have deployed Windows Vista since there was considerable kernel and device level innovation in Windows Vista. The Windows 7 release is expected to have only minor changes in these areas. Customers who are still using Windows XP when Windows 7 releases will
have a similar application compatibility experience moving to Windows 7 as exists moving to Windows Vista from Windows XP.
Historically, mainstream deployment occurs not when Microsoft releases a product but 18 months later. While the mainstream deployment cycle is beginning for Windows Vista now, it isn’t expected to begin for Windows 7 until at least mid-2011. With Microsoft set to release a new version of Windows every three years, there will always be a new version on the horizon during a typical evaluation period. This means that customers should not base their deployment decisions on the anticipated release-to-market (RTM) date but on an “evaluation completion date,” sometime after RTM and dependent on the
customer. For more information on deployment lifecycle, refer to Gartner’s report, “Don’t Skip Windows Vista entirely”, Gartner 2007.
Not deploying can also have implications for security, support, and regulatory compliance and reduce flexibility in the face of changing business requirements. Due to the lag time between typical OS evaluation and deployment, as well as the fact that many businesses deploy slowly following better hardware attrition cycles, companies who skip an OS release may end up relying on outdated software
as third-party vendors stop supporting older systems. For the vast majority of companies, deployment, application, and device support are well-established for Windows Vista, making it an operational best practice to begin migrating now.