Microsoft has updated the Exchange Remote Connectivity Analyzer site with the option to analyze message headers.
After a decade, we have a GUI tool to troubleshoot AD replication problems. It is called Active Directory Replication Status Tool.
Any customer thinking of migrating to Office 365 should use the O365 Deployment Readiness Tool as a prerequisite.
Another useful tool from DigiCert, to scan your network and find all the certificates deployed.
Microsoft has released a very helpful tool in estimating the network bandwidth used by the different set of clients. It is an excel file like the storage calculator.
The Exchange Team has released the much awaited free tool to capture PST files and import them into primary or archive mailboxes, either on-premise or in the cloud. It is a rebranded version of PST Importer by Red Gate and is named Microsoft Exchange PST Capture.
Microsoft has released a new version of Exchange Server User Monitor (Exmon), which is compatible with Exchange 2000, 2003, 2007 & 2010. The version is 188.8.131.52 and was released in mid Dec 2011.