Currency, Decimal and Duration have Zero properties, but Double and Integer do not.
I'm creating an Array(Of Object) full of default values depending on the "actual" type and the resulting Select Case is kind of odd-looking. I'd suggest adding that property to Double and Integer for consistency.
There's also an argument for String.Empty (alias for "") given that we have DateTime.Empty. For some reason I feel less strongly about that, perhaps because I don't really care for String.Empty vs "" in C# for some reason, however ... again, it would be consistent.