Age got nothing to do with it. I'm 37 and still enjoy burying myself in the hard, rythmic crunch of distorted guitars and booming bottom end of hard rock/ heavy metal...but I also listen to other things, depending on my mood...jazz, fusion, progressive rock, blues...hell...(dirty little secret alert) I even listen to smooth instrumental jazz...what is that called? It all depends on how I feel... But if I were to make a chart showing how often I listen to certain styles, Hard Rock/ Heavy Metal would dominate the pie... but thats just me..your mileage may be different.
my pie would be pretty split...i listen to a lot of rock i can't characterize with a name...like DMB...Sting and his old stuff with the Police...John Mayer...stuff like that...love anything with jazz fusion...i also listen to jazz a ton...particularly at work during the day...those two music styles i guess dominate my ears...then i listen to a lot of Sinatra as well, mostly because of my father's influence...classical at work...Chopin in particular gets a lot of my attention. I just don't particularly enjoy the heavy metal stuff...never have really, so you may be right that age has nothing to do with it!
You really have to check out Soulfly. I really liked Sepultura, but Soulfly is just at another level IMO.
Hey man, you forgot Tool. I also like to jam some of the following: Iron Maiden System of a Down (I guess they'll qualify) Molotov (even though they're mainly not, they rock very hard occasionally, i.e. puto and quitate que masturbas - perra arrabalera)