What he said. Also have you considered that people can type their password and even if they get it wrong it doesn't matter as their browser/password manager can still remember it. And even then they can always just reset it if they got it wrong.
Your form lacks affordance - it's not clear, despite the subscribe header, that one should complete it by tabbing/clicking and then entering data.
On the OP example at Huffduffer one clicks a "sign up" button (which has the mouseover feedback you lack incidentally) to get to a page which is for sign up. Hence the affordance is not so important as they're already in the "I need to enter data"-pipeline.
Also FWIW I think messing with default button formats should be avoided unless you're going to make sure that it's clearly a button (affordance again).
Maybe I can rank higher for juan corbett's name? http://alicious.com/2010/juan-corbett-name/