I'd agree with Hayden and say that the single channel 800's (2203/2204) are the best for rock/metal, purely down to the "plug and play" nature of the amp. No channel switching, no FX loop, no reverb, just a straight ahead valve amp that rocks.
The combo's do lack in bass, but I'd put that down to them being open backed cabs instead of using closed backs like the heads. The only thing I'd change on my 4104 (2204 combo) is giving it a reverb tank, other than that it's great, and apart from going down the head/cab route, it's a keeper. I even like it's tone with the 5881's it's running, where I've hated every 900 I've heard running that used the same power valves.