It's no wonder that PC companies that rely on Microsoft aren't waiting around to see how it turns out. With Apples OS X-powered notebooks that seize upon market share, Dell and Hewlett-Packard are in a hurry to add new features to their computers, as well as technologies that support Vista. And for some products, the computer giants have eschewed Vista altogether.
IDC analyst Crawford Del Prete said that people are going to see many experimentations in this space next year. Currently, while Microsoft is on a mission to restore the public image of Windows Vista, Dell and HP are keen to prove that they're selling much more than just a computer that runs Windows.
Windows 7 is much more than a simple Service Pack. With improvements in the kernel, user interface,networking system, desktop applications, hardware and device support, it seems to be closer to the realm of a mid-life update in the form of Windows 98 Second Edition or similarly the R2 editions of Windows Server 2008 or 2003.
Should Windows 7 become established or follow the above mentioned route, it introduces Microsoft with two instant challenges. The first is, what to call the OS ? If it's not an essential advance from Vista, and all signs show that is the case, then it would make sense to keep the Vista brand and advertise Windows 7 as a 'one step better' upgrade to Vista. Maybe this means that we can expect to see something similar to Vista SE, Vista 2.0 or Vista Plus.
The second challenge would be, is this Vista variant going to be a sufficient draw card for present owners of 
Vista PCs. Microsoft can't expect to set the cash registers ringing by throwing expensive computers onto the shelves. The smarter step might be to price Windows 7 in concurrence with its ‘upgrade' status. And maybe just make some of the major improvements available as a free download while attracting users to pay for the better stuff.
Another option is to consign the brand of Vista to Microsoft's company time line. A return to the simpler year-branding which Microsoft initiated a decade ago and which it retains for most of its client and server software, would end in Windows 2010. Certainly ‘twenty-ten' is a catchy name. Though such an action would mean a solid break from the past which Microsoft might not be ready to entertain and the substantial step forward from Vista (which Windows 7 is not), leaving the company susceptible to allegations that Windows 2010 is more like ‘Windows 2007 and a bit'.
Currently all the signs reveal that Microsoft's strategy with Windows 7 is to under promise and over deliver the precise opposite of the Longhorn/Vista experience. If so, Windows 7 will be forced to stay a Son of Vista instead of the Future of Windows.
Resources:
Putting Vista in order
Is it possible that Windows 7 could be Vista SE or Windows 2010?!