At this point in the state of hackerdom, passwords really need to have four things:
1. They need to be unique to each site
2. They need to be complicated (ie long, using upper/lowerase/numbers/punctuationifallowed)
3. They need to not be made up of words/phrases
4. They need to either be memorized or securely stored.
It's time to look at password managers. A password manager generates complicated passwords and stores them for you. You access them by putting in your one, secure password into the system to decrypt the passwords.
Here is a list of some password managers:
http://gizmodo.com/5876508/account-hacked-these-password-managers-keep-your-everything-safe
Personally I like 1Password. It's easy enough to use, and it can be put on my laptop, iphone, and ipad. I don't trust cloud password managers because they might one day get hacked.
Once I started using a password manager, which asks to store passwords as you use them, I was shocked to find that I had nearly 60 passwords collected in a few months. Not all of them are super-important. But the problem is if any of those passwords is the same as another site, your problem can spread like wildfire.