On the 3rd October 2013 Adobe announced they suffered a major data breach as reported by Krebs on Security . Recently security researchers have analysed the leaked passwords used by Adobe's customers, a news article by The Register shows this information clearly.
It turns out that 1.9 million users were using '123456' and another 3.5 million were using 'password' as their password. These passwords should never be used. You should always use a long complicated password with uppercase, lowercase, numbers and special characters.
Personally I use an online generator to generate a random password; and where possible I try to use 30 character random passwords for all the websites and online services I use. I then store this information in .txt documents and in a HTML page with a search box. These files are then stored in a TrueCrupt container with another unique master key.
It can be a pain having to copy and paste the passwords to log in, other options available would be LastPass or KeePass. As more and more people sign-up to services online it is hard to trust the encryption which the services offer; therefore it is vital to use a strong unique password for each service.