What we need, I think, is for browsers to display the CA as well as the URL. As in, 'DigiNotar certifies that you are connected to gmail'. This won't wholly solve the problem, but it will a) broaden the knowledge that CA's actually exist, and thus the problem of trusting them and b) provide some reputational disincentive to being a bad CA.
Unfortunately chrome seems to be headed in the opposite direction, removing the URL bar.