This is based on the number of their albums in my top 100.
1. Guardians (29) - This was the metal spirit that introduced me to the genre as well as the world. Songs like Dazed and Confused would influence many later songs that lured me in, oftentimes by bands such as Scorpions or Metallica or Dio. And then you add the symphonic stuff, much akin to the artist that my father introduced to me at 15: Meat Loaf, changing my world, and suddenly you've got the perfect clan for me.
2. The Fallen (23) - I feel like the Fallen has a bit of an unfair advantage with so many subgenres under its belt, but taking influence from the Sabbath side of things can in fact go a long way. There's metal that sends lightning through your veins, and then there's the stuff that crushes your soul. I can't deny that Neurosis had a big say on expanding my metallic horizons.
3. Infinite (19) - While most post-metal hasn't had much of a say in my metal affairs, the progressive and avant-garde stuff is the kind of thing that really gets my brain pumping. Starting with Dream Theater, I eventually moved to Tool, Symphony X and similar bands, and I especially love how it can move into practically any genre with ease, from power to death.
4. Horde (15) - As with many, my first venture into death metal came through Symbolic, and it wasn't long after until the heaviest shit imaginable was not but pussy to me. Although there aren't very many death songs or albums I could call favorites, they keep managing to find my way to my top 100 albums
5. North (14) - Sometimes you need to just sit down and embrace the darkness, or the sadness, whichever you prefer. Folk metal and viking metal are quite fun on their own, but the black metal easily outshines it on my charts. Nevertheless, Moonsorrow, which encompasses all three, is one of the finest examples of each of the three as well. It just sends you back in time the way LOTR does.
6. Pit (9) - Thrash was a pretty slow venture. Believe it or not, when I first heard Master of Puppets and Ride the Lightning, I didn't really get into them beyond a couple songs. But further ventures into heavy, power and death helped me to overcome that. Master of Puppets and Ride the Lightning have both spent time as my number 1 metal album of all time, although speed metal struggles to keep up with thrash's output IMO.
7. Gateway (5) - There is very little alternative metal that I'm in love with. The only example I can think of right now is Dirt by Alice in Chains because I went on many grunge binges in my early days online. Otherwise, quality alt-metal is something I appreciate critically rather than being engrossed in personally.
8. Revolution (5) - I love almost all kinds of punk. I went through various binges in a variety of punk genres, but metalcore isn't one of those that I've been able really grip beyond a few key bands. Especially when the subgenres like deathcore kick in, metalcore's more of a guilty pleasure rather than a serious venture. Still, I found that alt-metal can be much more imaginative in the whole, hence albums like Lateralus and White Pony.
9. Sphere (1) - Although I consider Killing Joke's Extremities an industrial metal album as well, there is extremely little industrial metal in my chart because much of it gets more monotonous than it needs to be, even the much better ones.