What is the correct content type for Excel 2007 content?

What is the correct content type for Excel 2007 content?

am 22.12.2006 16:36:00 von Roland

Our web application returns content with Content Type:
application/vnd.msexcel. The ASP component we use then formats the data as an
HTML

, which is interpreted by Excel 2000/2003 without any problems.
Excel 2007, however, shows an warning dialog which says that the data is not
consistent with the extension. Probably this has something to do with the new
file extensions of Office 2007. Our application should work for all Office
versions.

Does anyone know how to format the data so that no warnings pop-up and that
is accepted by all Excel versions?