We've made several enhancements and bug fixes based on community feedback.
Please go to our Mailbox Server Role Storage Requirements Calculator updates tracking page to see what is in this new version!
A blog post explaining the calculator is here and or you can download the calculator directly.
Read my favorites blogs:
Designing a backup less Exchange 2010 Architecture
Microsoft Exchange 2010 CAS Array – Steps and Recommendations
Appear Offline in Microsoft Office Communicator Server 2007
Microsoft Exchange 2010 Test cases