Ultimate magus allows you to advance both a "prepared" and a "spontaneous" arcane class spellcasting progression.
The most obvious choice would be Sor/Wiz, but Bard/Wiz works too.
There are several other choices on the spontaneous side.
But so far, only Wizard for the prepared side.
So is there any other class that fulfills the prepared requirement?
able to prepare and cast 2nd-level arcane spells from a spellbook.