By now pretty much everyone has an android/Iphone or blackberry and you can get a Bnet authenticator on those phones. If you don't have one you can get the keychain version very cheap.

Get the authenticator, yes its annoying if you play on a laptop and are constantly moving (I am and I have to reset my password once a month because of it) and yes its annoying boxing that you gotta log one toon in with the authenticator, hit esc and log the other 1-9 in a few seconds later, but you can't get hacked unless they have physical access to your computer in a location that you already entered your bnet code for that week.

As long as you go with out the authenticator you run the risk of being hacked. Don't let the hackers win, get the authenticator.