Advice on last skill

Just looking for thoughts on what my last skill should be. I currently have light weapon, block, heavy armor, alchemy, environment magic. I was thinking about attack magic, but didn't realize that most magic is useless in the expansions. I plan on playing a derth or etherim, probably a derth because I like the magic resistance, all the way through to the expansions. I am actually really bummed about the attack magic because I already started a character with attack magic and got to level 10. I really think that the attack magic is cool, and am pretty disappointed that you can't use it later.