Not here, over at Paladin's. He shows you why a good password is important. With numbers. [Link now dead, unfortunately. See the update below - Borepatch]
The only thing I'd add is that you can make it even stronger if you shift from a password to a passphrase. The problem with passwords is that as you add the complexity that Paladin rightly suggests, they get harder to remember. A passphrase doesn't have that problem.
Step 1. Think of a sentence you can remember. "Borepatch is the most boring Blog EVER!" is a good start. You can use anything you like, as long as you'll remember the sentence.
Step 2. Take the first letter of each word. I have "BitmbBE!" - pretty incomprehensible, but I can mumble it to myself as I type it.
Step 3. Profit! Err, or something. There isn't any step 3 - you got your passphrase in step 2.
And now head on over to Paladin's to see how long it would take someone to crack it.
UPDATE 29 August 2017 16:16: Peter emails to point out the link was dead, but also to point out that he has a password strength checker, on a page that has a great overview of how to create strong and easy to remember passwords. Recommended.