I've installed the 7.0.2 client on a few machines at work and my home laptop and one thing that hit me, cosmetically in the change in terminology of one Welcome Page in particular.  The Workplace page from 6.x is now just "My Work".

I found that interesting in light of what I read last week about Ken Bisconti's comments in regards to the Workplace.

So far, I'm very happy with what I'm seeing in the client, the server comes later in the week, I'm interested to see how the TNEF conversion goes, but I'll need to find someone I know that uses Exchange! Other items in the release that are insteresting are the SURunAs command -especially since we run a locked down desktop - and the ability to add columns to the ambiguous name dialog.  That will give you the ability to add columns besides the location and names - maybe Job Title - to help the user pick the right recipient.