Nobody else has mentioned physical security, yet. You may also like to consider the possibility of:

 1. Fire; do you have another copy of your private keys if your building burns down? Of course, storing additional copies adds additional risk of compromise.
 2. Natural disasters; depending on location, you may also need to consider the possibility of flood, tsunami, tornado, volcano. Also consider unnatural disasters such as war.
 3. Theft while unattended; if someone knew you had cryptocurrency of substantial value, might they just steal your computer hardware and read the contents of the hard disk? Is your password on a sticky note under your keyboard? (or on your monitor!)
 4. Theft while attended; ie if a thief held a gun to your head... 
 5. Hardware failure; storage media gets corrupted sometimes, or just stops working.
 6. Advising next-of-kin how to access the funds, without compromising them in the meantime.

I know this isn't a complete answer, but each case will depend on individual circumstances and this may still be useful enough to deserve an upvote :-)