I, the only one it seems, go with a pure, singled-classed mage. To be a spec sux, there will always be something from every school you want to use.
I would sugest you to chose a gnome and have 19 int (and as high wis as possible for lore) or import a BG1 mage whom have read the tome of int. 19 is a must for mage I think.
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We call him Bobby Corwen