My music taste hasn't changed so much as widened.
When I was 10 or so, I liked pop-punk like Sum 41 and Nu-Metal like Papa Roach. Whilst I fell out with that sort of thing for quite a while, I could now listen to an album without wanting to pop my own eardrums to stop the pain (and ever so often, I will do for nostalgia's sake).
As I got older, I got into heavier things such as Slipknot and Trivium, which later grew into listening to Death Metal.
It wasn't until I started listening to a punk/ska band called Rancid on a friend's recommendation that my music taste really expanded. I got into punk bands like The Clash and Gallows etc through them, and ska bands such as Reel Big Fish and Aquabats. Also, through the frontman's side projects, I got into Reggae (admittedly only a tiny bit). Again, I never stopped listening/liking earlier stuff I listened to, I just added to the list.
One thing that had been consistant was that I hated rap. Could never stand it. Then I listened to MC Lars and, surprisingly for me, I quite liked it. I got into other 'nerdcore' acts through him and also started liking a bit of Eminem too. All the while, I'll still listen to older bands/artists, as Rancid (and pretty much anything else Tim Armstrong has done) remain my favourite band.
Most recent addition to my music library? J-pop, mostly anime soundtracks. If you'd have told me three years back that I'd be listening to and enjoying that stuff, I'd have laughed. Funny how it goes.
So yeah, as I've said, my music taste hasn't changed. Just grew and expanded.
[sub]I still hate dance and dupstep though.[/sub]