Alexisonfire

This Canadian crew have been building a major rep for the last few tears since they formed in 2001. They went over hugely at this year's Download festival and will be playing the Reading/Leeds festival as well. One of the few bands to crossover between the hardcore, punk and metal scenes they can play as easily with Slayer as they can with Rancid.
They are a five piece with a big, aggressive noise that kicks like a mule but has enough changes to keep interest past the initial ‘whomp' from the speakers.
Elements of classic grunge crossed with old-school EMO and real melodies, the spitting/snarling attack eased by softer, plaintive vocals. Not the most original sound but done damn well.