Your email is a gateway to resetting passwords to almost all of your other online services - and there's a real danger that you could lose real money as a result.
Gmail's two factor security is pretty good and there is no reason why you shouldn't be using it. It secures both applications and computers; and prevents someone accessing your account even if they have managed to gain knowledge of your password.
So, if you haven't recently changed your Gmail password go and do it now. Then while you're there enable 2-step verification.
You'll be glad you did.