Hello,
Let's go with a review I tried to postpone as much as possible to avoid raging too much, but in the end here we are to review this light novel/manga/anime series called "Suzumiya Haruhi no Yuutsu" and all the variants/films.
Written by Nagaru Tanigawa, has been one of the hit of the last years with millions of copies sold (of the light novel).
Let's go with a synopsis and then whine a bit on this series :
On the first day of high school a beautiful girl named Haruhi Suzumiya introduces herself as having "no interest in ordinary humans". She asks for any aliens, time travelers, sliders or espers to join her. Watching her weird behaviour is Kyon who sits in front of Haruhi and is the only person who talks to her. When Kyon comments about Haruhi's joining every club in school and then quitting he unwittingly gives Haruhi an idea to start her own after school club. Thereafter Kyon and several others find themselves dragged, literally, into the Save our world by Overloading it with fun Suzumiya Haruhi's Brigade (the S.O.S. Brigade for short).
The story is quite original and the execution wonderful except for some director's decision.
First of all, the first season is aired in a non-sense order just to make things more "interesting"?! Don't know what was the idea of the director, but as for me that order created only rage in me.
Second thing, in the second season those eight repeated episodes of the time loop story were a "little" excessive.
I mean hell, in the original novel the story was closed in a short part of a single light novel and you give that story almost the full series? And all repeated content with little to no changes!
Character wise, we have a couple of interesting characters. I especially liked watching the relationship that is born and that increase over time between Kyon and Yuki Nagato.
There is growth in the various characters as the story progress and all the girls are pretty cute, Suzumiya included. If she would shut up her mouth will be probably the best of all of them as she has quite a nice style.
As far as the graphical quality is involved, I have no problem with either style or quality of the series. The film was literally stunning and the quality of the tv series was quite good.
The opening/ending of the two series were quite colorful and nicely animated.
The seiyuu involved with this project are top notch. We have Aya Hirano in Suzumiya Haruhi role, Minori Chihara in Nagato Yuki role, Yuko Goto in Mikuru Asahina role and even Daisuke Ono as Itsuki Koizumi.
Opening and Ending songs were quite an hit in Japan and the in-anime songs were quite beautiful as well.
Concluding, this is a series I can suggest to anyone that can survive without trying to kill Haruhi for her bossy attitude with everything/everyone.
This is not a nice series to start up watching anime as you would end up with too many questions that nobody has answers for. 
And yes, my favourite character is Nagato Yuki. She does get some spotlight over the course of the series (light novel one) and her character that slowly become more "human" is quite cute to see.
See you soon,
feal87