Another problem with simply choosing a strong e-mail password is that "password recovery" systems tend to be rather weak.

For example, you might have a great password like h48nu43@8;ng, but that's not very useful if it's too easy to guess your recovery questions. These questions tend to be things like, "Where did you go to elementary school?" and "What color was your first car?" If the hacker gets both of these right (and obviously these would be very easy to research and/or social engineer), he gets to reset your password to something of his choosing.

In general, once your e-mail address is known to hackers, and if you think you might be a high-value target (such as a high-limit poker player, or a known figure in the poker community), your best play is to both change the e-mail address associated with important accounts AND clean out your saved e-mail on that account to where it doesn't contain anything personal and/or important.