best mage skills...

max out heal, lightning, fireblast, weakness, nightmare, and both buffs. u can choose if you want the single ice-shot at all, but not necessary. life steal is well worth maxing out too, really. rez only needs one level, one mana pot is ok and that is only if you have like no regen.

the reason why you shouldn't max ice storm thing is because it offers the least damage, and the freeze time increase isnt really needed. 3 sec is enough to wait for bear to stomp or use firestorm for combo effects. also, mana shield lv 1 ONLY the extra armor is useless.

ps about the one-shot-ice skill, its usefull to combo bosses, the only single target you should bother on.