I have just watched till ep 50 but just like to put in a few opinions. I agree it will be interesting between neji and sasuke but Sauske's sharingan is pretty limited as it can only copy skills which are not of bloodline origin. Furthermore, he is pretty blinded revenge which is hindering his potential.

Still I think the one with the most potential is gaara cos his mound of sand seems is a very potent form of attack and defense! Even Rock Lee's primary lotus failed to cause much damage. I think Naruto is a bit overrated cos the nine tailed fox is mostly responsible for his high level of chakra and he seems to be too hot headed at times.