I try to avoid House Rules as much as possible; they're never properly playtested and invariably alter the game away from its core concept.
So by properly playtested you mean by professionals who come up with a "this might work" kinda rule, play it a few times and decide whether or not it works and then write it down?
Bah, humbug. Personalizing an RPG to match your vision of the world you envision is the very heart and soul of role-playing games. Without that we all might as well just run canned adventures the professionals dole out to us mere mortals. I'd rather, uh, come up with a "this might work" kinda rule, play it a few times and decide whether or not it works and then write it down.