This got me thinking about what a Giles and Ethan soundtrack might be.
For my own reasons, I skew Giles slightly younger than ASH, which gives me the full range of the fun mid-70s to play with, and the early days of punk.
Canon!Giles is associated with three pieces: a track from Cream's second album (1967), a song from Who's Next (1971), and the ever-amusing "Free Bird" (1973, a hit in 1975). Mainstream choices, utterly conventional. I bet Giles played "Stairway to heaven" when trying out guitars. We see some snippets of his record collection, including VU's Loaded, probably the most mainstream of their records. But it does kinda move him away from the usual 70s thudding luuded-out bellbottom thing.
Bowie. Eno, oh yeah. I can see Another green world in Giles' stack of vinyl, along with the earlier albums. (And ASH fans have got to like the idea of Giles putting on Music for airports on a rainy afternoon.) I don't think he got into prog, though maybe some ELP would have been attractive to a guy who liked the lighter classics such as Puccini. Any anybody Giles' age is going to have deep knowledge of the Beatles catalog. No argument.
Personally I hope Giles stayed in touch with the English folk scene and has Robyn Hitchcock in his collection. Don't know if I can reconcile that with "Free Bird", though.
The story of Giles and Ethan requires glam rock, though, and some shadings of punk. Like Elton Motello, "Jet boy jet girl", if you want Ethan's point of view. The Buzzcocks are too late for Giles, unless he continued listening to new music post-return to the Council. They're thematically right for a Giles/Ethan soundtrack, though. And put the Bowie in there. And some T-Rex. And Eno's first record. And early Roxy, before Ferry booted Eno and turned into a lounge singer.
Giles is shown playing a Gibson acoustic on the show. If I had to put an electric in his hands, it'd be a Les Paul. If he's got money to play with, he's got a PRS. Wanker.