I used to use a Terror 500 for Doom. Its a high gain amp but the distorted sound out of it is bloody awful. I'd always go with Ashdown, they work very well and are indestructible.
The sound city head may do the job, give it a try with a big cab.
The best setup I had was an Ashdown ABM600 in to an Orange OBC410 cab with a Darkglass B3K and Two Notes Le Bass for dirt