Yes I will cancel all of my AMEX cards in November. I intend to wait out the 18 months and sign up again and get the new sign up bonuses. This is what credit card churning is about. You have to be ruthless if you want to maximise points. The benefits of signing up again far outweigh keeping these cards.
I too would like to do cancel all my cards however the 3ppd for edge and 2ppd for explorer is too irresistible.
Do you have alternatives?