Warning!* Some spoilers below.
I really loved the first Naruto series and I at first I was obsessed with this one as well until they started in with SOOOOOO much filler. Filler out the ass and then a few actually story episodes, then another shitload of filler. I am finally fed up and dropping Shippuden till it's finished airing so I can skip over the filler completely. I strongly recommend you all do the same, also if you happen to have the addresses of those responsible for this mess of filler in place of actually story I would love to burn them alive for you. ;)
Sorry about the rant in place of a review guys but this HAD to be said so people who haven't watched this yet will understand that at certain points in this anime they will need to either skip the filler episodes, a list of which can be found online, or IF for some self deprecating reason they decide to watch the filler they make sure to keep sharp objects away from themselves so they don't cut their own wrists.
Over all Naruto and Naruto Shippuden are really great anime, the characters all have a great deal of depth and back story, there aren't many that I found annoying or unpleasant, (except Lee and Guy) .... Hang on flash back of Guy and Lee filler, gotta go puke real quick....
OK back now, anywho...
The story arcs are actually really engaging with plenty of interesting and powerful bad guys that helps to keeps things interesting. A few twists here and there are nice as well. By the time you get to the higher episodes you find yourself really engrossed in the story and wanting to know what happens next, of course you don't get to find that out till the filler is over, but still you hang on wanting to know. It's that good of an anime. I will most defiantly recommend this to any anime lover, despite my previous ranting because of just how much this series can drag you in, before long you actually care what happens to the characters of whom most viewers will pick their favorite and root for them big time.
Personally I am a fan of the Nine Tails. (I always like things that can wipe out a whole city ;) I mean really if they MUST do filler, how about some more back story on how the Nine Tails came to be like it is? Was it always evil or driven that way? The other tailed beasts seem to have unique personalities and during one episode we DO get a brief conversation between Sasuke and the Nine Tails that indicates he knows Madara, and if they have personalities they must have had some kind of life after being seperated from the 10 tails and BEFORE they became bound to the Jinchuriki (did I spell that correctly?), am I right?
Hell that could be 10-20 episodes of "better filler" right there! You know chocolate filler, instead of dog shit, OR how about some filler involving say the romance building between Naruto/Sacura/Hinata?
In conclusion this a GREAT anime with some ugly streaks of filler blocking it from getting a perfect rating.