most efficient defensive spells for sorcerer / wizard by level

[fel_horfrost]

What are the most efficient spells/cost effective defense spells on the sorcerer/wizard spell list by spell level?

[XMorsX]

0: Resistance
1: Vanish, Protection from Chaos/Evil/Good/Law, Mage Armor, Shield, Illusion of Calm, Expeditious Retreat
2: Invisibility, Mirror Image, Levitate, Protection from Evil, Communal, False Life, Alter Self, Resist Energy
3: Magic Circle against Chaos/Evil/Good/Law, Fly, Ablative Sphere, Displacement, Monstrous Physique I, Undead Anatomy I, Communal Resist Energy
4: Shocking Image, False Life, Greater
5: Stoneskin, Communal, Polymorph, Undead Anatomy II
6: Form of the Dragon I, Battlemind Link, Mislead, Undead Anatomy III
7: Spell Turning, Giant Form I, Polymorph, Greater, Hostile Juxtaposition, Greater, Walk through Space, Fly, Mass, Form of the Dragon II, Statue
8: Polymorph Any Object, Prismatic Wall, Moment of Prescience, Form of the Dragon III, Seamantle, Undead Anatomy IV
9: Time Stop, Shapechange, Freedom