Good computer passwords should have letters, numbers and symbols. I found a good source of all of those: the ship numbers for Star Trek vessels.
On one particular program for which I have to change my password occasionally (it's a work-related site that you'd have no access to), I started working with the different starships named Enterprise, starting with NCC-1701 from the original show and first three films. I've continued to the NCC-1701-A from the later movies. Now I'm at the NCC-1701-B. (And another bonus: you can use it with or without that second dash, making it harder for someone to decipher!) The NX-01 from the show Enterprise doesn't work for this, but we can skip it and go on to the -C, the -D, the -E...heck, we've even gotten a glimpse of the NCC-1701-J!
See? I'm helpful.