C'mon you gotta love the original Star Trek series at the very least. I mean it was a milestone and it's still my favorite of all the Treks out there.
The fact that it has so many communities (for Trek in general) shows that it really resonates with people across the board. I can't think of many other shows that have achieved that. Its the mix of science fiction and adventure with very human emotions and problems that make it so appealing, I think.