Being an IT type in a past life, and having had several classes on security and hacking --

I've found that im most cases, I can either find or guess a password in under 2 minutes, if I know the person. One friend was flabbergasted when I guessed his password, then totally freaked when I guess his second one on the first try (hint: his son was in cub scouts - the passwords were webelos and tuocs, not really toughies, as he had some scout stuff in his office).

I can't stress enough having characters in your password. Even just two numbers in there will take the probability of guessing from maybe to no way Jose'.