Safest to store
1) Paper
2) Trezor/Ledger
3) Ethereum Wallet/Software
4) Metamask
5) Mew
Yeah, These are some main options for storing ETH.
I think if you has less than 10 ETH => Just use: Mew or Ethereum Wallet/Software
If you have more than 10 ETH, you should by a hard wallet/ cold wallet, such as Trezor/Ledger
Believe me, even when 0.1 eth is stolen, there is not much to enjoy in this situation.
Personally, I use a MEW and store data on paper and in an encrypted file on a flash drive. In addition, I add extra characters to the private key.