The Soviet Union is definitively number 1, followed by the Nazis, then the British, then the Confederates. The umbrella of Islamic terrorism is a distant fifth.
I don't care that you guys hate Middle Easterners, but Islamic extremism isn't more of a threat than Imperial Japan was.
They killed 3,000 Americans on 9/11 and we've been at war with them since 2001. They are big villains in our history and still a threat to this day.
Have they killed 161,000 of our troops?
This is a good point -- I would put them ahead of Al Qaeda, but still behind Britain.