When I was a teenager, it was rock - Metallica, Motley Crue, Def Leppard, Megadeth.
In mid-twenties I started listening to industrial - NIN, Ministry.
That sort of led me into techno, then by late twenties/early thirties I was listening to a lot of drum and bass.
Sort of went into dubstep after that, but after forming a band with some friends I've recently started getting back into guitar based music, really stripped down un-produced music like the White Stripes and the Kills.
But I haven't given up on any of the music from the past - on my MP3 player I've got AC/DC, the White Stripes, Seasick Steve, Burial, Bob Log III and many others.
I don't think of it as so much a changing of musical taste - more like a broadening of horizons.