Thrash used to be for me, but I've found many thrash bands outside the popular ones and the once-in-a-while out there ones, it's a REALLY stale genre with one of the stupidest attitudes in metal.
I'd say melodic death metal is easily one of my favorites, if not that then straight up death metal/black metal. Folk metal/power metal definitely deserve a mention too.
Come to figure, after writing this, I really don't know. I guess for the sake pick of a choice I'd say melo death. But again, all the aforementioned are still valid.
"We praise an act of charity, yet shrug at an act of achievement."