After reading book 6 of the Harry Potter series, I am convinced of a few things:
First and foremost, Ginny Weasley is a big Phish fan. No doubt she went through a brief Dave Matthews Band phase, and will always love "Under the Table and Dreaming", but she fell in love with Big Red (Trey) a few of summers ago when she apparated with her brothers Fred and George to a trio of shows at Deer Creek. Fred and George were selling all sorts of stuff in the lots (no doubt some of their famous Polyjuice Potion treats, among other things), but the the Moby Dick show on 7/11/00 really blew Ginny away- it linked up her love of Led Zeppelin with Phish. Phish will always be her favorite, but post-Coventry Ginny has has been getting into Sound Tribe Sector 9.
It should not surprise you that the Weasleys are all really into the Jam scene, with the exception of Percy, who doesn't "get it". Ron Weasley loves Gov't Mule and the Allmans, as well as Widespread Panic, but still is somewhat skeptical of George McConnell. Arthur and Molly Weasley were big Deadheads in their day. Arthur is still a little spaced out by all the acid he took in the 70's, and Molly could make a mean space cake. No doubt strange acid trips with Muggles started Arthur's fascination with simple muggle artifacts, like a rubber ducky. Arthur has repeatedly asked to use Dumbledore's pensive to relive (or remember) some stellar shows from '77, but Dumbledore is more of an Elvis Costello fan and doesn't understand why someone would want to listen to so many noodling guitars anyway. Bill Weasley thinks that the jam scene is good- I mean, he was raised on the stuff, but Grunge hit while he was at Hogwarts and to this day he is a huge Pearl Jam and Nirvana fan.
While Mr. and Mrs. Weasley were on Dead Tour, Sirius Black and James Potter were at Hogwarts listening to Zeppelin and Pink Floyd while on top of the castle. Where do you think Sirius got the idea of turning into a Black Dog? Lily was more of a Joan Baez and acoustic Dylan fan. Harry shares a lot with his father's taste and is also into Zeppelin and Floyd, but now has become a huge Radiohead fan. Harry really loves the live performances and moodiness of Thom Yorke. He also likes some darker songs by the Cure, but OK Computer and Kid A are tops with Harry.
Hermione, being Muggle born, has a knack of uncovering new bands all the time. She was the first to bring Bright Eyes, The Flaming Lips, Modest Mouse, Wilco, Deathcab for Cutie, and Rilo Kiley into the Gryffindor common room. She will always love Joni Mitchell and is a huge U2 fan. Hermione loves to get behind a good cause, and so does Bono.
Few people realize how big of a Metal fan Neville Longbottom is. Neville really has a lot of rage inside him but doesn't have a lot of confidence, and for some reason Metallica really speaks to Neville.
Hagrid is a big ZZ Top fan. 'Nuff said.
The Slytherin house has never been that musically inclined as far as taste goes. Snape doesnt listen to music at all. The Slytherin girls really like the Pop of Britney Spears, J-Lo and The Backstreet Boys, which somehow seems to fit. Malfoy has never been one to buy a cd, because we all know he despises Muggles, but Crabbe and Goyle have turned him on to a few Creed and Limp Bizkit records.