I do like Gaara, he is totally powerful. but the best thing Gaara did was become friends with Naruto. it made him a better person and gave him some purpose. Naruto seems to rub off the right way on everybody who befriends him.
Itachi was definately, deadly and powerful but you have kept up with naruto. Sasuke has given up everything even his friends to gain more power,and he has become way, way, more powerful now. He even killed Orocchimaru. Eventually it will have to be Naruto who is going to have to take him down.