So you setup a brand new SharePoint 2010 site and found that like MOSS, it can be a pain to get the Datasheet View working - to wit:
"The List Cannot be displayed in Datasheet view for one or more of the following reasons"
You may also have problems with the GridView - this solution fixes both problems. The problem is that the Office components needed are not installed, SharePoint 2010 needs BOTH the 2010 and 2007 components to work properly.
The guaranteed fix is to do the following (do this in order - x64 MUST be installed before x86, i.e. 2010 before 2007.
1) Install Office x64 (does not have to be licensed)
2) Download and install:
Microsoft Access Database Engine 2010 Redistributable
3) Download and install:
2007 Office System Driver: Data Connectivity Components
After these, run and IIS reset and off you go!
SIDE NOTE: If you want to run a copy of SharePoint Designer on the server (i.e. a staging or test environment), you must install SharePoint Designer x64 BEFORE the 2007 Office System Driver.