Jon Potter said:
In other news: I was sort of half-considering a themed approach to spell selection. That theme? Light. Flare, Daze, Dancing Lights, Light of Lunia, etc. Including some "related spells" of course, light Magic Missile and Scorching Ray.
I'm not sure though. I am discovering the reason that I rarely play spellcasters, though. What I think makes for a cool caster is mechanically unsound. :\
It sounds like you want a "blaster" that has a divine flair and a themed set of spells.
This screams out "Arcane Disciple" to me. Basically, the feat lets you add a cleric domain to your arcane spellcasting list. So you can select the "Good" domain and throw down Holy Smites and Protection from Evils, or the "Healing" domain and function as a party healer.
Another possibility is a Divine Bard. Bards are ready-made hybrid casters.
A third option would be a cloistered cleric with the Magic domain. Cloistered Clerics feel a lot like wizards (D6 HD, lots of utility and divination spells, light armor, poor BAB), but have full casting progression and are mechanically sound.
A final option would be some sort of simple Gish: Since you want Charisma synergy, I'd suggest Paladin 3/Sorcerer 3. Focus on spells that do not have somatic components or have long durations (True Strike, Featherfall, Blindness/Deafness, False Life all come to mind) and you can wear plate mail; you'll be able to use your turn undead attempts to fuel Divine Feats.
Basically, to build a functional caster, the goal is to lose as few caster levels as possible. Nearly everything else is a secondary consideration. There are better ways than multiclassing to add arcane spells to a divine caster or divine spells to an arcane caster.
