My remark about browser interoperability, and Opera's browserability prompted a little re-exploration of some HTML (thanks Wade and loonyboi in particular) which fixes the search box spacing under Opera by making the whole contents frame a form. Since my understanding is that Opera is truly HTML compliant, so the answer to my question of whether Netscape or MSIE had it right, is neither did.

Here's a little separated at birth, cooked up by Jack "morbid" Mathews: