A couple of months ago I downloaded the public beta of Office 2010. Overall it seemed fine although it was difficult to see what was really changed. Most of the apps looked essentially the same as in Office 2007 except I did notice that Groove was renamed to SharePoint Workspace. It seems to work the same (with some small enhancements) but overall, it looks the same to me.
The one exception to this was Outlook 2010. It didn't sync correctly with my BlackBerry so I couldn't use it for long and had to revert to Outlook 2007, but the one feature I really liked was the Social Network integration. This is similar to how smart phones sync with Facebook (and how Linked In should) so the profile picture and phone numbers stay in sync with what your contact has listed on the site. This is a great feature to help ensure you don't have stale email address or phone numbers which both seem to change a little too often now a days. In Outlook 2010, Microsoft allows 3rd party developers to create connections between Outlook and what ever internet service they want to help sync the information.
This integration is made most obvious through the "Person Pane" (see to the right) in an Outlook mail message although you will see it when you open a contact directly as well. This single feature would have pushed me to upgrade to 2010, but Microsoft did something unexpected that will make me rethink that...
They released this feature as a free add-on to older versions of Outlook. You can download the beta version of Outlook Social Connector
which works with Outlook 2003 and 2007 (and of course this is built into Outlook 2010). Once you have the Social Connector installed, you can get the connector for LinkedIn from their site for free
as well. You can expect that a connector for Facebook will be forthcoming after the release of Office 2010 (or perhaps even earlier), but for now, I'm happy with LinkedIn
since those are the contacts I'm not concerned with anyway.