Naruto is a series with millions of fans the world over and a truly unforgettable cast of characters. But so is Jersey Shore.
This series is one of many which are popular mostly due to their wide variety of characters and "cool fight scenes," but unfortunately, Naruto has very little to offer on the quality writing front. Please note that, at the time of my writing this, I have not yet seen a single episode of the sequel series, Shippuden--and for the best, because this is a review solely of the original 220-episode anime, just as Shippuden's review will be one on its merits and its alone. No room for bias here.
Writing: I will credit Naruto--at the very least, it was free of the many glaring plotholes present in Dragon Ball, another series popular for similar reasons. And the military/political aspects of the show, while certainly not Code Geass or (further yet) Ghost in the Shell deep, are relatively sound and significant to the plot. Where the series really falls flat on its face is in its lack of consistency. A well-planned, well-written series sets laws for itself and then follows them, thus creating a believable world for the viewer--by contrast, the physics of the world of Naruto, much like Superman's powers, depend mostly on what's convenient for the situation, and are usually given a half-hearted explanation some time later. This "do something cool and then scramble for some kind of explanation" style of writing is sorely detrimental to the experience of the show and makes it blatantly clear where the creator's priorities lie: It's all about flashy fight scenes, and the plot's just there to fill the gaps between them. Michael Bay fans rejoice.
Art: The artwork and animation are fairly typical for the era. There's no great amount of detail in the lines or fill, and the animation, while not choppy, is no more fluid than other similarly-produced anime series. All in all it's another par for the course, visually.
Sound: I've seen the show both dubbed and subbed, and the quality is pretty interchangeable. Naruto's voice is just as grating and obnoxious in both cases, and the rest of the cast is neither greatly- nor poorly-performed. Despite many long outdated beliefs, the dub is also uncut. The soundtrack is actually one of the series's stronger points, though--the mix of rock with traditional Japanese instrumentation works well as the calling card musical style of this series, and is both recognizable and reasonably well-composed. I must give credit for that.
Ultimately, Naruto falls into the same trap that so many other series--shonen especially--fall victim to: A very distinct prioritization of action over story content. If you're just looking for some cool fight scenes between characters with cool powers, shows like Bleach and Naruto will more than satisfy the need. If you're looking for a more intricate plot in an immersive setting with dynamic characters, you probably won't find much fulfillment in Naruto.