As a proud owner of Windows XP NL (Dutch version) I tried out a few tricks yesterday with the new fancy ObjectDataSource in ASP.NET.
I bound a class to a gridview that contained several properties with one of them having a DateTime type.

Showing the values of my object (using nHibernate) in the gridview worked like a charm, but updating the values was problematic.
I got stuck with an error that my DateTime field could not be converted from System.String to System.DateTime.

Then I added some localization settings in my web.config that set the currentCulture and currentUiCulture on nl-NL.
But still the same error. Then I tried to set the culture settings on en-US and guess what.......it worked!
Okay, my DateTime field was now shown in US format and not in NL format but at least updating works now.

So it seems that the ObjectDataSource has a nasty localization bug!