I've always said my favourite Genre is Metal, and I expect the range of bands I class as metal can sometimes be a bit wider than other people's. Looking through my ever increasingly eclectic collection I've just realised that many of my favourite bands don't have enough elements or be aggressive enough to be classed as metal.
So the top 7 in my list I pretty much love every album. No 3 is a bit different because although I like less than half their stuff, the songs they write that I do love can top (only slightly mind) the rest below. Same goes for Opeth but I'm only just getting into them and I'd say I love more than half their stuff, just that when the Mars Volta get it right, it's right enough to be several places higher on the list.
The other 2 bands in the bottom 3 are for 1 specific album only, although, I like a bit more of them than that, these particular albums I would rather listen to than 95% of the rest of my music.
2. System of a Down
3. The Mars Volta
4. Arcane roots (NOT Arcade Fire)
7. Rage against the Machine
8. Incubus (S.C.I.E.N.C.E)
10.Rob Zombie (Hellbilly Deluxe)
A Perfect Circle
Nine Inch Nails
Guns n' Roses (I know, but more metal in attitude and sometimes sound than most Rock bands of their era.)