Greetings escapists, first post here for me but i've been a long time lurker, regularly visiting and having a peruse after watching the latest zero punctuation. I saw this thread though and I had to post - because i've experienced exactly the same phenomenon.
I was more a symphonic metal man, i.e. Nightwish or the more mainstream avenged sevenfold but also loved the classic heavy metal - maiden, priest, megadeth etc. I was a metal or nothing man.
However, in the last year my music tastes changed drastically. I love a bit of deadmau5, chemical brothers etc. Basically anything electronic/techno/house.
My favourite is wolfgang gartner - see
http://www.youtube.com/watch?v=bt4H7S0Yc_0
(fast forward to 1 min in to get rid of the introduction). If you like that, also try looking up Skrillex - slats slats slats.
I think this is because I've always loved music that gets my adrenaline going, music that makes me feel alive so to speak. I love all the different instruments in metal in the same way I love the construction of electronic and house. Its all great music, but your tastes probably havent changed as much as you think they have - you're listening to music that is similar in construction, if not in sound. Just brain farting here though, could be completely wrong!