Is there way to test for both 0 and NULL with one equality operator?

I realize I could do this:

WHERE field = 0 OR field IS NULL

But my life would be a hundred times easier if this would work:

WHERE field IN (0, NULL)

(btw, why doesn't that work?)

I've also read about converting NULL to 0 in the SELECT statement (with COALESCE). The framework I'm using would also make this unpleasant.

Realize this is oddly specific, but is there any way to test for 0 and NULL with one WHERE predicate?