Windows 7 Release Candidate
Why it's important: The Windows 7 RC is the final major pre-release milestone version of Microsoft's next client and its almost all good news. The Windows 7 RC features a slew of minor user interface changes, Internet-based media sharing via Windows Media Player, and compatibility with an exciting new compatibility feature called XP Mode (see below).
XP Mode and Windows Virtual PC Beta (for Windows 7 RC)
Why it's important: The next version of Virtual PC will only be provided to licensees of Windows 7 Professional, Enterprise, and Ultimate, and it will come with a fully-licensed copy of Windows XP with SP3 that you can run in a virtual environment. As with Microsoft Enterprise Desktop Virtualization (MED-V), however, Windows Virtual PC also allows users to simply run virtualized XP applications inside of the host Windows 7 environment, foregoing the complexity of two desktops, each with their own applications. Did I mention this was free?
Windows Server 2008 R2 Release Candidate
Why it's important: Windows Server 2008 R2 is being co-developed with Windows 7, and while the R2 name suggests a pretty minor release, this one is a doozy. It includes major advances to Hyper-V (including Live Migration capabilities), new PowerShell 2.0-based management interfaces, major power management advances, and other new features. But the RC is jam packed with new stuff, too, including some previously secret Hyper-V enhancements, impressive performance and scalability gains, and more. Some stuff I can't talk about yet, so expect a full R2 write-up in the near future.
Microsoft Hyper-V Server 2008 R2 Release Candidate
Why it's important: Microsoft says that "Hyper-V Server 2008 R2 is a stand-alone product that provides a reliable and optimized virtualization solution enabling organizations to improve server utilization and reduce costs. With the addition of new features such as live migration and expanded processor and memory support for host systems, it allows organizations to consolidate workloads onto a single physical server and is a good solution for organizations who are consolidating servers as well as for development and test environments."
Service Pack 2 for Windows Vista and Windows Server 2008
Why it's important: Windows Vista and Server 2008 are now being serviced by a single service pack, which should make deployment easier. But there's lots of new functionality in there too, including Windows Search 4.0, Bluetooth 2.1, Blu-Ray data disc writing support, exFAT file system improvements, simplified Wi-Fi configuration, support for VIA 64-bit processors, and more.
Find out more: Windows Vista/Server 2008 Service Pack 2: What to Expect
Microsoft Office 2007 Service Pack 2
Why it's important: Office 2007 aggregates all of the security and other updates Microsoft has delivered through February 2009, but it also provides some interesting new capabilities. These include significant improvements to the stability, performance and interoperability of the Office suite. That latter bit refers to compatibility with non-Microsoft file formats like PDF and ODF, the Open Document Format. Some of the biggest performance improvements are in Outlook: Microsoft reports that that application is 26 percent faster than its predecessor on a set of common e-mail tasks and is even faster, at 35 percent, with larger mailboxes.