I can't stress enough how important a mirror is for riding in traffic. Your incident is a classic case of why a mirror his helpful; you would have had a better idea of what was behind you before the engine started revving, and could have pro-actively chosen the best course of action for the situation. As someone else said, you could have faded right a bit to give yourself more room; if that wasn't feasible another thing I've done is simply use the hand signal for slow/stop (and to catch extra attention, open and close fingers kind of like flashing. It's funny how even with an aggressive driver, signaling to indicate you realize they're back there will usually make them back off. The other thing is that once I've made enough room for them to pass safely I wave them around and they usually appreciate that you know you're there and you've given them the all clear to go around.

As far as mirror recommendations go, I prefer a helmet mounted mirror.