I guess I've gone through several phases, really.
*Phase 1 - Around when I was between the ages of 13-16, I listened to Metal. It started out with Linkin Park which was my first favorite band. Back then they were so badass, the rapping and the metal combined was something that I guess appealed to a lot of youngsters, and they were pretty big on my school in general. From that it continued with bands like System of a Down, Slipknot, Disturbed, other bands that could fit under the "neo/nu-metal" tag, bands that were metal but also had a couple of other elements to it, I suppose.
From the nu-metal bands that I had previously listened to a lot, I began to dive deeper into more classic stuff within the metal tree. Bands like Iron Maiden and Metallica became two of my big favorites, and they were bands I quickly bought a lot of stuff with, and started listening heavily to. I would also say that Helloween played a part, while they are part of the power metal-tree, I was more appealed to their slightly heavier side. "The Dark Ride" for example was my favorite album by them.
After that I slowly started getting into heavier music featuring growl/scream-ish vocals. It's interesting because I didn't really like that kind of vocals at first, but my friends really liked it, so it was popular back then to sort of follow and listen to the same stuff. I got adjusted to more harsh vocals after a while and really started enjoying it. Got into Melodic Death Metal with bands like In Flames and Soilwork, but also a lot of Metalcore with bands like Trivium and Killswitch Engage. What I enjoyed with these genres was that they were both heavy, but also had a melodic side to them.
*Phase 2 - At that time I was starting to get a bit tired of metal. There wasn't really anything wrong with it, but I felt like a lot of the bands I was listening to had their "sound" that they were sticking to, and I guess you could say that I wanted more variety in my music. Three big bands came to form my outlook on music and change my life in this phase, Opeth, Tool and Dream Theater. They were all heavy like music I had previously listened to, but they started to build something within me, an interest in hearing "odd" and unexpected things. While they were all heavy, they offered so much more then just heavy music, lots of dynamics and melodies that would forge themselves in my head. Dream Theater for me was sort of like the bridge from metal to other styles of music. While I don't listen to Dream Theater anything today, I can still appreciate their music and enjoy it, but it reminds me of a time in my life that I don't really like, and that is partly the reason why I don't like them as much today. Another reason is that I've gotten pretty tired of the whole long solos, fast solos and the so called "wankery". Tool and Opeth are two bands that with me in another way, two bands that I listen to a lot today, still.
*Phase 3 - After the bridge that Dream Theater, Opeth and Tool opened up, it was like having a key open up a door to a room full of treasures. I was able to look at music from a whole other view, and appreciate music that I could never have appreciated 3-4 years earlier. Bands like Porcupine Tree, Anathema and Radiohead paved the way for my music-taste, and from that it would branch out completely.
This is what I would call my current phase. Everything I have discovered in this phase is music I still listen to actively, compared to the music from the first two phases (except Opeth and Tool), which I don't listen to much. This phase includes pretty much everything I listen to now, so it's too much to namedrop in one post.