This will probably stop some drive-by hacking - great. But my understanding from some well informed people, is that increasingly rootkits can hide their network traffic.
So, whilst this will add piece of mind, you'll still need to maintain security - because all this will really do is let you know you've been "hacked" again. Sure, it may prevent the dropper from connecting out - but often that would look like Flash or Java just connecting out to a random host.
As someone who got hacked, and installed NoScript, I'm amazed at the number of hosts that even mainstream websites connect out to. I struggle to stay on top of my whitelists. I just don't think you're going to see the dropper in time and stop it.