I've seen both seasons, and The Melancholy of Haruhi-chan Suzumiya, which was a webshow spinoff thingy.  It was really funny, too (They also have another spinoff thing, but i never saw it personally).  I also have a copy of the light novels to read sometime, though i really wish i had a hard copy.  The endless eight didn't bother me much, I thought it was okay.  It was kind of fun to find the differences in the episodes and whatnot.