Windows 7 is Microsoft's next client operating system. It will succeed the current release, Windows Vista. There has been some talk about whether the company would retain the name "Windows 7", which has been used so far, to refer to the OS, and it is the name that release candidates carry. Mike Nash, Vice President for Microsoft's Windows Product Management has confirmed in his recent blog post, that the OS retains the name "Windows 7", for its commercial release. Nash stated that since it's the seventh major release of the client OS, it would make sense calling it Windows 7.
Nash explained the thought behind not giving it a name based on its release date (eg. Windows 95/98) or using "aspirational monikers" (eg. Windows eXPperience/Vista), by saying that since the company doesn't release a new Windows version every year, and that using an aspirational name did not do justice to what they were trying to achieve. It made all the more sense caling it Windows 7, being the seventh release