I think we all agree hardware wallets are the only really secure storage.
Mobile, PC, or online is more useful for spending, but you can transfer coins to those wallets in small amounts and reduce your exposure.

Along those lines I just finished searching hardware wallets. There are several, but it really comes down to just 2: The Trezor or Ledger Nano 2

Numerous reviews have pointed out that they are nearly identical in function. Trezor has a slight edge in a more mature interface, but it's slight. The only feature that I've found that is different is that Trezor allows you to create hidden wallets in addition to your regular wallet. This is a feature that might be useful if you were forced to give the password and open your wallet (such as police, border crossing, getting robbed at gun point etc.) You could open the standard wallet with no indication of any other storage. Only you know that it is there. That's a cool feature. Question is is it worth an additional $75

The Trezor  has recently gone up to about $150 (I see people mention it is $100, but not sure where). The Ledger is about $70