Apparently talking about the new Office 11 beta is all the rage, so I'll throw my 2 bits in the mix. 

Outlook

As a PM, I use Outlook far more than the other Office apps.  I have to admit that with beta 1, had my doubts about the viability of offline mode, but it seems to be fairly solid in beta 2.  I still find myself reaching for the "Send / Receive" button and switching between online and offline modes to coerce Outlook to retreive mail.  Our IT folks have even sent mail telling us *not* to use the "Send / Receive" button as it was taxing the server.  I found that at least a little amusing.  In the end, Offline mode is nice though.  I no longer have to worry about syncing mail before I stray away from the warmth of a wireless AP. 

Word

Reading mode, reading mode, reading mode.  What else do I need to say?  There also seem to have been improvements to the pasting intelligence.  I've been using the "Keep destination formatting" smart tag less than I used to.

InfoPath

I see this product and I wonder how many times are we going to reinvent the form designer wheel?  The context menu metaphor InfoPath uses for property editing is not intuitive in my opinion.  I do agree with other folks that it wont be long before someone creates an ASP.NET (and hopefully Windows Forms too) adatper that converts an InfoPath form to a live app.

As far as useage, I'm not sure I see the market for this app.  I will be interested to see how businesses put it to work.