One of the safest & easiest ways to store your ETH, Tokens, ETC, BTC, and many other coins is via a Ledger Nano S or TREZOR. Both are hardware wallets. Both work with MyDashWallet.org or other services like MyEtherWallet.com. And both cost less $100, if you hold a high amount, having a good cold storage solution is a absolute must.
In theory, as long as you keep backups of your keys and don't visit any malicious / phishing sites, and never use remote access software, and don't install any malicious applications, then you should be fine. However, we hear from folks every day who lose, misplace, destroy, or have their private keys and funds stolen. It only takes one mistake to lose everything.
The hardware options give you peace of mind, are easy to use, and are becoming a must-have for anyone storing more funds than they are willing to lose. I would personally recommend it for anyone storing anything over 2wks salary.
The device itself holds the keys and signs transactions for you. MyDashWallet is integrated with both Ledger and TREZOR, so you can even use the same interface you are already familiar with. This ensures your keys aren't ever on any internet-connected device. Phishers can't get them. Malware can't get them. Keyloggers can't get them.
When you set it up you will write your key (24-word backup phrase) and store it offline in a secure secondary location. This prevents you from losing access to your funds if something were to happen to your hardware wallet.