Having two large Angels can have aggression issues. Usually it is one per tank, almost regardless of size. Angels are my favorite fish, but I plan on putting only one large Angel in my 240g. I'm going to try two dwarfs (already have a Singapore Angel and am considering adding a Multi-bar or multicolor too)... maybe even a Pygmy.
I agree with the too many Tangs thought too. If your group is good with one another, I'm not sure I would risk adding another and possibly disturbing that group dynamic.