It depends on how you want to use your coins. If you bought it as an investment to hoard "long-term" I would go for cold storage. {paper wallets}

,but if you want to regularly use these coins... I would suggest that you buy a hardware wallet. {Trezor} I would avoid the online wallets and

services where you do not have the ownership of the private key. {also exchanges used as a wallet}  

I came to the conclusion its the best for me to devide it! Small amount on some exchanges! Bigger ammounts on online wallets or pc wallets with 2fa! And a big ammount in cold storage! Because what if you are so stupid to loose or break your cold storage.
Also devide some under your close family like brothers and sisters or if you have high tech parrents!
Oh yeah and lets also be honoust! Lets keep some cash on the bank or in real estate!

Like this you won't regret to much in the future!

i agree cold storage cannot be hack and also you can retrieve it when you lost your cold wallet as long as you have the private key and there is one thing you can count on to is the paper wallet meaning you will right it down your private key on a piece of paper and keep it on the safe place that would be the safest thing you will do.

Software wallet, the wallet.dat and other files backed up on USB, the textual info, like username and passphrases written into a text file, not saved and a smartphone takes a picture of that text file that is then deleted without ever saving the data.

USB drives can corrupt or just stop working entirely -- for that reason they are not meant to be used as your main way of storing your coins. In order to grant yourself access to your coins basically for ever, it's utterly important to have your private keys printed on a piece of paper, or have it engraved on a piece of metal for extra durability.

Actually keeping bitcoins offline is not that hard and slow as people might be thinking. A lot of people say that spending bitcoins should be kept in online wallets but actually offline wallets are same too they just need to be kept synchronizing since that is the basic thing. I don't think you can be hacked with offline wallets unless you have some malwares in your computer.

The safest way is to keep you coins where you have full control over your coins,which means you have the private keys to your coins,the rest are just ways to store your coins for the mean time and the risks involved are many as anything could happen,but if you could save guard your private keys then it is the best way to save your asset.

i think every wallet we know its safe to keep bitcoin and its depend for us how we keep and save that wallet. as long as only us that will know the place and what is the private key, then the wallet its still safe and no one can used the wallet. i am prefer with offline wallet and android phone wallet but for android phone wallet, we need to hide the wallet from the other people that maybe will hack our wallet.

Offline is always the safest.

Trezor or paper wallet for myself.

I think that poeple are overreacting when it comes to online wallets, i mean what is the safest using an offline wallet and storing your coins on desktop where you are vaurnable for hacks and your pc could stop working and you can't do a thing about it, or store them on online wallets where they are stored on servers with complete secuirrity.