#3
Mike Thompson has a signature amplifier from Rivera. It's called the KR7 and is very expensive, but supposedly based on the tightness and dryness of a Diezel VH4. He could of been using a Diezel at the time actually, or another Rivera.

His guitars are usually pretty standard affairs - Ibanez with active Seymour Duncans or BC Rich with something similar. It won't make a huge difference, really, as long as you have 24 frets, a quick fretboard and active pick-ups.

Here is a list of his stuff in more detail:
http://www.slipknot-metal.com/main.php?sk=equipment