So, blessed as I am with a Microsoft Technet subscription I downloaded the Office 2010 beta and installed it over the Office 2007 installation I had. There were several things I noticed straight up. The big icon in the top left corner of the software is gone and replaced with a file tab that has all the options previously hidden under the big button. Outlook is substantially changed and I like the changes, with one small exception thus far. The black theme that I liked very much in Office 2007 makes it look sort of busy and isn't quite what I expected. I guess that it will get better in the full release to come (or at least I hope so).
The ribbon being used in Outlook is a welcome change. I didn't like the way it was in Outlook 2007 - after all, why have a new look if it doesn't get spread around all the programs in a suite? I've always liked the functionality of the ribbon, despite the dislike it has engendered in some circles. I dread the teaching of it's usage to my clients, but we'll see how it goes. Overall I think the direction Microsoft has taken Office is a good one. I'm a big proponent of OpenOffice but I find the interface clunky and unpleasant. Microsoft's Office is better in terms of the interface. To be honest, I don't have a lot of time to screw around with desktop software, but I do like the changes to Office and screwing around with it is interesting. The interface changes are smooth and look good.
I'll write an update once I've spent a couple more weeks and keep an eye on things as they develop. All in all, I currently like Office 2010!