I suppose I have something of a confession to make in regards to this topic. I haven't really bothered to explore music that much for quite a long time now, and most of the stuff I listen to these days is game soundtracks. So that means a lot of the bands I used to think of as a favourite at the time (Scar Symmetry, SOAD, Persefone, etc.) I've kind of moved on from, even if I still like them. And as for newer stuff, I can't really justify calling them my "favourite" because either I haven't explored their full discography as much as I should (Igorrr), or I'm not familiar enough with the surrounding context of bands to say this one in particular is definitely the best (Caligula's Horse), even if I still think both are brilliant. That said, I suppose there is one exception to all this; one who has remained through all the years. Devin Townsend. But Nekro already posted him so I think I'll pick something from an older favourite for the sake of variety.
Consciousness (pts. 1&2) by Persfone.