The most secure client would be armoury i just set it up - it took 2 to 3 days for it to sync up.  You can also use it to start a cold storage system.  It also helps to use another os (linux) as they are alot harder to hack.  Theres even a page on how linux is more secure on ubuntus website.  It sounds like a man in the middle attack - hope this thread helps show people that online wallets are unsafe for large amounts of money.