The best way to prevent being robbed of all your Bitcoins at once is to make sure that your holdings are spread out over multiple wallets in different locations. Many people do not like the hassle of administering ten different wallets, but losing all your money is certainly worse. By spreading your Bitcoin in small amounts, losses in the event of a security breach can be minimized.
At the very least it is advised to use one wallet address as a checking accounts, a public address for sending and receiving Bitcoins, and one as “secret” savings account. The number of savings wallets can be increased as the number of Bitcoin owned increases. There is no limit to the number of wallet addresses that a person can have.