I'm way late on this, but here's my $0.03471 worth (I recently passed my Security+ exam).
The best password is a passphrase that has the following characteristics:
1. Length - the longer, the better. 20+ characters.
2. Complex - don't use just lower-case letters. Use a mix of upper- and lower-case letters, numbers, and characters like ! @ #, etc.
If you have a password that is ten characters long and all lower-case letters, that's 26^10 possible combinations.
If you have a password that is twenty characters long and uses a mix, that's 64^20 possible combinations.
Passphrases like (don't use any of these, these are just for example):
1 d0n't 0wn @ c@R, AnYmor3!
&I'm ju5t g0ing t0 k33p tYp1ng Un7!l MY f1ngErs F@ll oF$