Do not use an online wallet, unless it's like Circle or Coinbase because those two (and possibly more) will reimburse if there is a loophole and their bitcoins get stolen. Blockchain does not and will not reimburse you for what they lost, and it has happened. I'd go with Electrum or MultiBit, because the only way to lose your coins is either you wipe your HDD, you get RAT'd, computer HDD fails, and so on. Which is all very unlikely if your smart. So go with an offline wallet.