Casting Spells.
Throwing spells.
Not summoning spells (unless, a Summoner of course...).
My point is should the Wizard lunge a fireball? Should he wave his arm horizontally as he shoot out an energy flux of magic missiles? Should the Wizard "dance" as he's pulling the forces of the mysterious unknown?
Avatar: The Last Airbender, springs lots of thoughts. I'm personally standing on the "if resources allow" side. But damn.. it would be so freaking badass cool...
http://www.youtube.com/watch?feature=player_detailpage&v=oCXHi0kFucc#t=78s
EDIT: Not that^ flashy, look at the movements of the characters. Reduce it reasonably to a fantasy setting like Baldur's Gate.
I think the animation in Baldur's Gate is some singing hand magic jazz hands, in Dragon Age: Origins (and World of Warcraft), Skyrim too, the Wizard lifts one arm or something and that's that.