Some bands definitely fit in a category (I agree with Trivium and their ilk being purely (power) metal). Others, like, DT, its weird to argue what style they are. To me, badass bands are the ones that write whatever the hell they feel like writing, not caring about adhering to a particular style and not trying to be different on purpose (oddly, the same criteria for determining a 'cool' person for some). Compare SymX's Communion and the Oracle vs. Set The World on Fire. Two totally different styles for one band! Or DT's Another Day (Pop), Lie (Metal), or 6 degrees (everything in between). I always thought that 'prog' and 'fusion' meant, among other things, an aggregation of styles to create something new. Anyway, I usually only like bands that can't be placed into categories for a poll like this, and oddly, most of the bands mentioned straddle all of those styles IMO.
I do like the rest of it as well, but my favorites are just Power, Death and even a little Black Metal 
