The plague is treatable with antibiotics if caught early as it is a gram negative bacteria. In addition, we even have a couple vaccines and they are working to make them 100% effective. The plague isn't the end of the world, we have many cases of bubonic and even pneumonic types within the United States every year.
I still say that Ebola is the far greater threat; we have no antibiotics, antivirals are minimally effective, we have no vaccine, and it is a RNA based virus that is prone to mutation. At this time, we just treat Ebola patients for the symptoms until the bodies own immune system beats the virus back or dies trying. The good news is that we may be able to synthesize a vaccine from survivors, but contrary to popular belief that will help against one strain only and is useless when it mutates.