At our recent NAV User Group conference, I had the pleasure of seeing some new NAV 2009 functionality demoed by our local Microsoft ERP Expert.
In the demo, Sue set a filter on a list of records (I think it was a vendor list) and then from the Actions command menu selected a new option called "Edit in Excel".
This looked similar to the Send to Excel feature with one difference. There was a new button on a Dynamics NAV tab of the Ribbon that allowed the data to be updated.
In the demo, Sue deliberately set the Responsibility Centre in the spreadsheet to an invalid value and the update returned an error message that the Responsibility Centre was not valid. She then corrected the data in the spreadsheet, hit the update button and the data was updated in NAV.
This was a fantastic demonstration of the new NAV 2009 web services in action. I'm pretty sure this option is not available in the Marketing Beta Release that is available to partners and the image Sue had was based on Windows Server 2008.
It looks like there's definitely more cool stuff coming in the NAV 2009 release and this ability to edit data in Excel is going to prove extremely useful to many users.