[Bozos of Bones]

Clerics, Druids, Paladins, Rangers - Wisdom.
Sorcerers, Bards - Charisma.
Wizards, Specialist Wizards - Intelligence.
People like Aasimar make great sorcerers because of the Charisma bonus. High main casting skills gives extra spells and makes it less possible for enemies to resist the spells. As for skills, take Concentraion and Spellcraft. Assign others as you want. Extra Intelligence adds more skill points. Next, out of feats, Subvocal Casting is the first must, then read up on them and choose what you will. As for alignment, take whatever.