Any password is hackable with enough time. Everyone has seen the charts where the longer the password, the longer it will take to crack it, up to several or even hundreds of years.
That's not so true anymore. With password cracking machines with multiple GPU's and cloud based services designed for password cracking, any password can be cracked in a matter of minutes. Anything in a dictionary, bible or wikipedia can be cracked in minutes. Password dictionaries know about e = 3, 1 = i, etc... Don't think adding some numbers and characters into your words are making it harder.
The only chance is for a completely long and random string of characters. A password manager of some sort is required to keep all of this information secure.
Anything is better than using the same password for multiple sites, no matter how complex you think it is.
A yellow pad kept in a desk drawer is safe from hackers, but not someone that breaks in to your house. The odds your password will be hacked from a website are much greater than someone breaking in to your home.
There are offline and online utilities for convenience. I wouldn't recommend a password protected spreadsheet only because most spreadsheet passwords are easily bypassed. If you're copying and pasting, go long and random. It's the same effort to copy and paste something short as it is something long. Find out the longest password the website will accept and go with that.
No matter which method you use - make a BACKUP.