Bands? Most electronic music is made by a single musician, only occassionally multiple.
Anyways... ignoring that fact... Skream is regarded as the god of dubstep. Boxcutter is awesome too. Vex is kinda cool, quite raw. Distance produces some nice stuff, one of the few artists to have a whole album. I rather like Cruel Culture and Polarity, but no-one seems to have ever heard of them.
Need a fat subwoofer to listen to this music though ^ ^