All-in-One utility to optimize, tweak, tune up and clean up your Windows Vista. It bundles more than 20 different utilities in one! Get access to hundreds of hidden options to improve system's performance and security, clean registry, junk files and defrag Registry, optimize network to speed connection, uninstall program smartly, mange startup items, and many other miscellaneous utilities. It is an excellent companion for windows Vista.
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Install this update to address a set of known application compatibility issues with Windows Vista. After you install this item, you may have to restart your computer.
This update is provided to you and licensed under the Windows Vista License Terms.
Download: Here
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ieXBeta is allowing its members to create a list of software, that will work with Vista RTM (Build 6000), or won't work. The list is fairly detailed; it is much easier to check the list than to install a given program.
View: Windows Vista RTM Software Compatibility List

Source: IExBeta ... more

Windows Vista Upgrade Advisor is designed to help Windows XP users identify whether their PCs are ready for an upgrade to Windows Vista, which edition of Windows Vista meets their needs, and which features of Windows Vista will be able to run on their PCs.
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vistasp1.net has posted links to six hotfixes set to appear in Windows Vista SP1 (Service Pack 1) codenamed Fiji. All six fixes can be obtained via Microsoft Support if you can prove that you are indeed having the problem listed. The site links directly to Microsoft KB articles that describe each problem in Vista.

929734 - You may experience problems after you resume a Windows Vista-based computer from sleep or from hibernation
929191 - IBM and Lenovo computers may t ... more

TweakVI - The first software designed to both tweak and optimize Windows Vista.
Tweak hundreds of hidden features of Windows Vista, optimize your machine and customize it to your needs. The best tweaking software ever!
The main application of TweakVI together with many plugins is available completely for free. Additional plugins can be downloaded after subscribing
Unlike other tweaking utilities, TweakVI bundles lots of different utilities in one. It was developed to combine both tuning and optimizing features to increase the speed of your Windows Vista system. It's the worlds first software for Windows Vista to combine both customization, tweaking and optimization features. ... more

A source close to Microsoft has confirmed to me that Windows Vista will in fact carry the build number 6.0.6000. He found this out by receiving a mail with the build stamp "Microsoft Windows Mail 6.0.6000.16384" so that ends that speculation.Also the MSDN subscription page has been updated with the following information

Windows Vista and Office 2007: Availability on MSDN Subscriber Downloads
Windows Vista and Office 2007 will be available through MSDN Subscriber downloads within 7 days of release to manufacture (RTM). MSDN Subscriptions is committed to making new content available to our subscribers as soon as is practical.

Several key Mi ... more

vista_5840.16384.061018-1900_x86fre_client-LRMCFRE_EN_DVD.iso
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The Microsoft Windows Mobile Device Center Beta 3 enables you to set up new partnerships, synchronize content and manage music, pictures and video with any Windows Mobile 2003 or Windows Mobile 5.0 powered device. Windows Mobile Device Center Beta 3 is only supported on builds of Windows Vista™ RC1 or later.

Download : Microsoft ® Windows Mobile Device Center ® Vista ™ Beta 3 for Windows (x86)
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Microsoft is currently getting ready for the Windows Vista RC2 release. This build, 5744 has numerous improvements and advancements in performance. 

To see the preview of the download page:
http://download.windowsvista.com/preview/rc2/en/download.htm

Microsoft is currently getting ready for the Windows Vista RC2 release. This build, 5744 has numerous improvements and advancements in performance.  To see the preview of the download page:  http://download.windowsvista.com/preview/rc2/en/download.htm ... more