Now, I love Naruto and all, and I think Kishimoto is great with his characterizations and sheer lack of filler for a manga that's still running, but I always felt that Kishimoto made a serious mistake when he had Dosu killed off.

Dosu, if you recall, was basically the leader of the Sound gennin who participated in the Chuunin exams. His ability was that he could transmit sonic waves through the devices in his arms and do things like mess with a person's equilibrium and cause internal bleeding and such. He attacked the ears, more or less.

He was also VERY capable, and clearly a step above his teammates. He was smart, rational, knew his own powers very well, and knew when to run away. Actually, now that I think about it, had he still lived, he would have had the potential to become a Chuunin.

After the Forest of Death, Dosu wanted to prove to Orochimaru that he couldn't be taken lightly, and that was his goal. Dosu wanted to show Orochimaru that he wasn't just cannon fodder for Orochimaru's purposes. He fought and won his preliminary match against Chouji.

...then he was killed by Gaara for the sake of showing off Gaara's demon.

I feel that they should have used someone else for this, or at least have Dosu severely crippled so he could come back in some form, but for him to have died, I feel it is a character that has been wasted.