+1 to Coinbase.
While nothing you can do can prevent a Mt. Gox situation, you can protect yourself individually from fraud and theft by making sure you setup multi-factor and setup a wallet. There are a number of good step-by-step illustrated guides available by googling “how to setup a bitcoin wallet.” When using multi-factor, keep in mind that you really need to use a TOTP (Time based One Time Password) application like Google Authenticator or physical key like Yubikey as SMS and e-mail are easy to retrieve if you are being targeted.
Also, of note for US citizens, you and a legal obligation to report any earnings from trading crypto currencies.