Exchange Best Practices Advisor gets a visual overhaul and new features for v2.6

Enhanced support for clusters, and other little 'nice touches' that make this program even more of a 'must have' for anyone doing Exchange work. Worth more than the price of admission (free) and catches a lot of problems before they impact your organization.

It has also been known to make some system integrators look bad by how many items are setup incorrectly. There have been many times I have used this program to fix a server I have taken over from someone else that didn't know what they were doing. Don't be that guy. Use this program.

http://blogs.technet.com/exchange/archive/2006/04/05/424431.aspx