[Lord Ludtke]

Try PI out a couple times, and you will see it's the most powerful spell in the game. It's damn near bordering on cheating.

I don't think you should pick nec or illusionist, as they are pretty powerful spell groups. I went through as an illusionist, and not having animate dead and Abi's HWilting can really hurt you. And missing out on PI on the other side would cripple you.

I was going to say most alteration spells can be replaced or done without, but Melf's MM says its evocation/alteration. And eventually Time Stop(boy, this is tough....)

Just pick out the spells you use most often(be sure to try out PI) and pick the school that eliminates the fewest of them.