Nice thread.
I dunno what my favorite subgenre is these days because I listen to and appreciate different styles everyday, but back in my metal heyday it was definately technical death metal. Here's how it happened with metal for me:
1986/87: I was listening to stuff like Iron Maiden and AC/DC when my mate gave me a tape with Master of Puppets on one side and Ride the Lightning on the other. My life changed forever.
89: Discovered thrash metal by way of Kreators "Extreme Aggression" album. Started getting right into Slayer, Coroner, Sodom, etc.
90: I heard Deaths "Spiritual Healing" on community radio and was absolutely blown away. I couldn't believe that anything could be so heavy. I was still listening to heaps of thrash and power metal, but death metal started taking over.
91: A glorious year. So many great death metal albums were released. Florida made its mark. I was listening to as much dm as I could get my hands on. Deicide, Morbid Angel, Death, Entombed, Napalm Death, Atheist, Obituary, Cannibal Corpse, Pestilence and Coroner all released classic albums.
92/93: Spent these years living in England, playing in a death metal band, listening to heaps of death/grind, and going to see every death metal band that toured. I think Brutal Truth's "Extreme Conditions...." album was the pinnacle of my extreme music appreciation, before I got bored with it and started listening to Alice In Chains and Soundgarden.
After that I listened to less and less metal and in about 95 I got right into funk and jazz. I've listened to so much different music between then and now, but I came back to metal eventually of course. Now I'm trying to get somewhat educated on what's gone on while I wasn't into metal, and what's going on now. And I've got a whole new appreciation for the stuff that came out back then. Hurrah!