This page is so very under construction. Bear with me, will ya? Thanks...
Buffy: The Vampire Slayer The Series
This is the version of Buffy most people are familiar with, and around which most of the fan fiction out there that I've read is centered. These characters are more developed, because there's been more time to write about them and get to know them, and their dynamics are fun to watch. My favorite relationship dynamic right now is the whole Buffy/Giles relationship. (I'm using the word in the context that a 'relationship' is how two people relate to each other.)
The Watcher and the Slayer are bound to be close to each other. They may not be friends per se, but each duo is connected. The same is true for Buffy and Giles. Joss and Co. haven't really explored their feelings about each other in depth. One of the really solid emotional moments between them that I can think of is at the end of "Passion" when they are outside of Spike and Dru's burning warehouse after Giles has attacked Angel for killing Jenny Calendar. (I can just hear Cordelia: "God, Run-on much!?") Buffy decks Giles and tells him he's not allowed to die, etc. Another is at the end of "The Dark Age" when Buffy tells Giles that he's allowed to be human. Anyhow, I think that their obviously close friendship deserves more exploration than it has been given.
I'll climb down off of my soapbox now. After all, Joss is god, and we are but his lowly minions. If he wants it explored, it'll get explored, no?