Haruhi is one of those shows that are popular because they honestly are that good, but everyone is watching it already, so let's leave it at that.
What you should also be watching, however, is Mushishi. It's a nearly perfectly episodic show about a fictional world, which I think is more or less an alternate turn-of-last-century Japan. In this world, there exist primitive supernatural life-forms called mushi, which only some can perceive directly, but which affect the lives of many in different ways.
The main character is a travelling mushi expert who helps people experiencing various troubles because of them. The episodes that are not purely stand-alone explore his past and current situation, but also do so in a way that does not break the overall flow of the show.
The premise is supernatural, but where the emphasis really lies is human nature. The mushi serve as a narrative device to put the characters into where they must make difficult decisions. The show is beautiful in the way in which it shows how much remains the same no matter how much may change. I would go so far as to say some of the episodes remind of Graham Greene in their treatment of the subject.
What really makes the series work as well as it does is that it is all very well executed. It maintains its atmosphere by both visual and aural means in a way I can only describe as highly succesful. It is well put-together from the general colour scheme to the way the characters talk. The only grating weakness is the opening theme, which is best not enjoyed.
My post ended up long and rambling and I probably failed to say what I meant to, but my point is that Mushishi is one of the best anime series I have seen (I dare say this even with four episodes yet unaired) and I encourage everyone to give it a try.