They're both neutral to me in terms of character, but I would probably have to pick Sasuke due to recent events him his personality misconceptions, justified.
(Mainly because I hated Part 1 Naruto's personailty so damn much.)
Sasuke. One of my most loved characters in any piece of Literature. I wouldn't even have delved into Naruto if it wasn't for this character. He has shouldered this entire manga and acted as a catalyst on many occasions. Through him one can see that Kishimoto's writing is not entirely down in the drains.