Re: I'm tired already just reading it
No good having a secure backup if you can't remember the 30-character password allowing you to mount your Truecrypt volume so you can enter your other 30-character password etc.
Make sure that the encryption phrase used is strong and lengthy. I typically run to thirty characters including the whole range of non-alphanumeric ones.
I don't disagree that password strength is important, but it can also be extremely counter-productive.
In a previous job, unencrypted laptops being returned from abroad had to be escorted to ensure foreign eyes couldn't peruse any data that might be on there. Encrypted laptops could be sent unescorted (the particular encryption software/mechanism was mandated etc).
The reset procedure for a laptop that had been locked out by too many (>3 IIRC) tries of the decryption passphrase was to return it to base, a real PITA for everyone involved - especially if the user's posting was in the back-end of nowhere.
So, encrypted laptops started turning up, unescorted, with the encryption key written on a sticker just above the keyboard. In other words, for anyone laying hands on the kit, they effectively weren't encrypted and should have been escorted. Those stickers had, of course, materialised because the boys on the ground were fed up of having to return the laptop to the UK so regularly.
Had the decryption phrase been a bit more memorable, those stickers wouldn't have been needed, and the security - whilst technically weaker than with the longer phrase - would have been more robust.
So, personally, when dealing with real-world users, having an immemorable 30-char decryption phrase represents a weakening of security because the requirements it imposes on the user almost guarantees they'll find an insecure way to work around it.