You know, I started off more of a gen fan than anything else, and there are still some non-canon couples that are awfully popular that I don't quite... get somehow. But slowly I have developed an obsession -- um, I mean, you know, a casual, not at all addictive interest, really no problem -- with Giles/Oz. The two of them work so well together somehow.
Baked, by
katemonkey, features Oz, well, baking, when of course you-know-who walks in. It's G-rated but very sweet.
The Collection, by the same author, looks at what it would be like if Giles and Oz merged their record collection. I would so love to see that collection.
Nine Songs, by Dolores, also focuses on Giles' and Oz' mutual love of music. Dolores pinpoints in one passage why I, at least, think the pairing is so beautiful: "There was a small irony in the fact that just about the only member of Buffy's small gang Giles felt able to talk to was the one who talked the least. ...In Oz, for all the boy's Californian inflections and surreal tangents, he saw something of himself as a younger man."
Marmalade Toast by Jane Davitt features Giles wondering about Oz' hair change colors. It's G-rated (hmm, for all that there are smutty stories I like I seem to be picking the tamer ones tonight) and fairly short. She just nails both characters beautifully.
The Baleful, Ingenious, and Curious Memory-Theater of One Ethan Rayne, by Glossolalia, features Giles and Oz and Ethan and a creepy carnival. It's long and so perfectly detailed that you can just see them there.