To be honest, because you'd definitely need cleans here and there, I'd recommend you get an amp that excels in cleans / mild overdrive, and plug in a high-gain distortion pedal like perhaps a Digitech Metal Master or a Boss MT-2 Metalzone. You get the best of both worlds... But of course get a good distortion pedal. A cheap one won't do your tone any good, and might degrade the tone of the amp if it isn't true-bypass.