Ebola wouldn't work for a large scale attack. I mean, sure, if they had some kind of ebola spewing bomb, they could infect everyone at a train station or something. But, after that it wouldn't get very far. It is far too deadly and far too quick to cause a real epidemic; especially in a country with decent sanitary conditions. Transmission is actually rather hard.
The reason anthrax was so fear was because it was the opposite. It was airborn, spores could survive extreme conditions, and had a longer incubation period. The symptoms are also very similar to the common cold at first, which most people just shrug off. Plus, we no longer vaccinate against it, and that leaves us vulnerable. Well, not me. Thanks Air Force! =(