[color=red][edit by mod: SPOILER WARNING][/color]
If I was supposed to tell someone my opinion on this series, I would say "read the first story arc, and then get off while you still can."
The Mist arc was fantastic, and was worthy of the praise that people generally give the series. However, after the awesome beginning, things sadly went downhill.
The focus of the story seemed to shift from Naruto proving himself to Sasuke... being the envy of the ninja world as everyone said how great he was. If the story was supposed to be about Naruto as he became a great ninja, why the sudden change? This is sad because Naruto was an interesting character originally, but he wasn't treated the way that he should have been by the plot, and is just annoying. In fact, nearly all of the three "main" ninja, Naruto, Sakura, and Sasuke, are annoying.
Kishimoto created many other interesting characters for the supporting cast, like Rock Lee and Shikamaru, however, the interesting characters that the fans want to see more of are shafted, instead so we can see everyone angst about Sasuke.
Also, the pacing of this series is heinous. Just about every fight from Naruto vs. Neji onwards drags on past the point of reason. Information is revealed painfully slow, to the point where you just want to beat the creator with the "hurry up and advance the plot, dammit!" stick. We even had ten chapters once dedicated to A SINGLE FIGHT. That equals about five full anime episodes of "final attack" after "final attack" after "final attack," over and over and over.
However, not everything is bad. Some of the later fights, like Rock Lee vs. Gaara, are extremely well done and emotional. Also, you can see potential for this series shining through, even if it was handled horribly.
Basically, the basic problem with this series can be explained in one scene: In one chapter after the third Chuunin exam, we are reminded how Naruto stresses that there are "no shortcuts to becoming Hokage." Literally less than two chapters later, we see him jump at the chance to learn an advanced technique so he can bypass the basics, which he never learnt. I wanted to like this series, I really did, but it was too much to handle asthe story dragged on... and on...