What should I upgrade?

Hi. I feel like I'm getting close town hall 8. I want to know though, what should I upgrade now, and in what order? Here are some pics of my base, and feel free to suggest what I should upgrade next.
http://i57.tinypic.com/2cd2sh.jpg http://i60.tinypic.com/evcg0w.jpg http://i59.tinypic.com/2qi3er7.jpg http://i60.tinypic.com/260bqyd.jpg
*also, please dont say anything about the actual base, it's just temporary- long story

Mortar, Air Defenses (still have 3 level to do each), Archer Tower.

gMortar , Air defense, and Wizard tower then do the others
Don't double layer your wall, wallbreakers can damage both at once