actually- a second wiz doesn't sound half bad...or better- a sorc. If the wiz doesnt mind being a utility caster- the sorc can be the blaster. Offensive spells galore.Oni :
Another wizard, you can never have too much arcane firepower. Wizards feed off of each other, they can share spells and share the burden of item creation. Having an extra one around makes it easier to have a good mix of combat, buffing and utility magic. Two wizards working together can go a long way toward helping the party past obsticles.

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.