Well...the obvious, the 1040 you mentioned is black where as the the 1080 is Antec Metallic Gray. The 1080 comes with a place for a fan in the side panl where the 1040 has a solid panel. You can purchase a panel with a fan and/ or window in it for extra.
The only other difference I know of is the 430W Truepower with the 1080 versus the 400W Smartpower with the 1040. The truepower is a far superior PSU, but the smartpower is still very respectable and near top of the line.
Brian