I think, Sakura is uber-important.
Well, we need her for the "2nd Naruto generation" (series following after the now running series is finished ^^), because she has to give birth to to her and Naruto´s son [img]i/expressions/face-icon-small-tongue.gif[/img]

Anyway, kill her off with a super dramatical scene, highly taking effect on many other characters (Wow, now, that i think of it...Naruto´s inner demon would instantly be completely released XD).