Cold Sweat.
Maybe a ceramic Nailomb if you want something 'hairier' sounding in the bridge, with a Cold Sweat neck.
The Cold Sweat bridge is nice and tight, cuts through well and is well suited to both standard and low tunings.
I have a CS set and I've found it to be a big improvement on the alnico Nailbomb, which I found to be more hardcore in character, although this makes it good for Sepultura and it was nice for Possessed.
The CS I think is much more versatile. If you want a middle ground between the A-Bomb and the CS, go for the C-Bomb, as I said above. There is a post here in a recent thread of someone playing Slayer on a C-Bomb in a Les Paul through an Engl amp, sounds pretty great.