For full on doom action, the Warpig has my vote as well.
That said, in my case I wanted to be able to reach for the doom, but be able to back it off as well, so I went for the Crawlers (just showed up in the post! :D). But I think that the amp vibe (and your is 'tude) and going to be a big component of doomy sludging. Plenty of more "classically voiced" pickups that don't get too midrangey will work pretty well, I reckon: Mules, Emeralds, Crawlers. A more open tone with big piles of amp gain would work fine.
But for the mother of all chug, it would be the Warpig.