I'll have to experiment a bit with that one...I've generally been a summoning freak- and early in the game, chaotic orb's the non-summoning spell I use the most. Then I generally have my mages use the spells to poke holes in the enemy's defenses, and have my clerics do the actual attacking with their offensive spells.
The spell I find I use the absolute most is Improved Invisibility. I just have this fondness for being sneaky.
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Playing the cutest li'l Chaotic characters since 1996.