The Unholy Trinity of 1986

All great albums but I'll have to say Pleasure To Kill.

RIB barely beating Darkness Descends.

I'm a big Slayer fan. Always have been. Reign in Blood is one of the best influencial metal albums, along with Peace Sells and Scream Bloody Gore, in my opinion.
But there is just something I have always loved about Darkness Descends. I think people overlook this album when talking about influence and just straight out GOOD thrash. I had to sit here for a minute and decide which to vote for out of RIB and DD. I have all 3 albums, Pleasure to Kill getting the least spins. Lately I have listened to Darkness Descends more than Slayer. Perhaps next month I'd vote RIB.
They are that close in my mind.

Darkness Descends was the best thrash album of 1986. No contest.

Ain't heard any of these albums for at least 15 years..... but from memory Pleasure To Kill would be the best.

The power of German Thrash compels me to vote PLEASURE TO KILL!