Pig Destroyer is a great band, probably my favorite from Scott Hull... though I do like Agoraphobic Nosebleed as well, "Frozen Corpse Stuffed with Dope" is an amazing album, which has been called "The Paul's Boutique" of Grindcore". "Altered States of America" is also cool, "Honky Reduction" was the first I heard from them and also enjoy.
Another band that I have not seen mentioned yet (though have not looked at early posts) is Brutal Truth, "Need to Control" is a must hear album for the newcomer.
oh, and I suggest this album as well:
and another project with John Zorn:
Guts of a Virgin - Wikipedia, the free encyclopedia
both of these are just insane records, jazzy grindcore.