Wolf Dog, if you cancel your Exede account you will NOT be able to use your WildBlue.net or, Exede.net email address any longer.
I'm sorry to see you go but, before you do, I would recommend getting a free email account, like Gmail and using a forwarding service on your WildBlue email sort term until you get your email address changed at all of the places you need to change it.
Bev is correct. You will lose those email addresses once the service is cancelled and would no longer have access to those emails. I second doing a free email account via Gmail, Yahoo and the like as those are not tied to any particular internet provider