Hey 
I always keep saying to everyone around - KEEP AWAY your coins from a web.
Whatever it is - exchange or web storage, or web wallet.
2FA will be of little or no use - if there is nothing left to connect.
My order of preference for security is :
#1 Paper wallet
#2 hardware wallet ( NANO, Trezor etc)
#3 Clean cold smartphone
Then comes maybe a PC or web.
You may ask what? Smartphone?
Yes. It is still better than anything on the web.
Just buy a cheap ( can be second hand) smartphone, update the FW to the latest, erase everything, make reset to FACTORY defaults, install only the minimum required apps, wallets etc, store your coins there, place proper PIN and protection measures on it, recharge battery fully, switch it off, remove battery, and put all in a locked safe. You may check and recharge the battery once in a while, every 2-3 month. DO NOT use this smartphone anywhere, ever. Let it rest in your safe all the time.
TO my belief, you get this way to PRETTY MUCH TO THE SAME SECURITY as with NANO or Trezor, with even some extra capabilities and flexibility.
However still my
NUMBER ONE is PAPER wallet
How to build a paper wallet in a truly secure way is yet another story. Not as simple and easy as you may think. I may have my blog post on this one day soon.
RE: Seed Key & Cryptocoin Storage (get off your computer!)