This is obviously a subjective question, and limited to the musicians you know of.
I think Martin Lopez (hoping he gets better) is the best metal drummer. I can't think of any other drummer that has the touch and feel that he does.
I think Mikael has the best metal vocals. I consider him the best at mixing various styles (death & clean) and doing both well.
I can't say that Opeth has the best bass or guitar players. I'm taking nothing away from the individual talent in these areas. I've heard some pretty phenominal bass and guitar work by other bands, so it's difficult for me to say anybody is the best at their craft in these areas.
I think Martin Lopez (hoping he gets better) is the best metal drummer. I can't think of any other drummer that has the touch and feel that he does.
I think Mikael has the best metal vocals. I consider him the best at mixing various styles (death & clean) and doing both well.
I can't say that Opeth has the best bass or guitar players. I'm taking nothing away from the individual talent in these areas. I've heard some pretty phenominal bass and guitar work by other bands, so it's difficult for me to say anybody is the best at their craft in these areas.