They sound a LOT like power metal...I'm talking European power metal here...you know, Rhapsody, Stratovarius...VERY similar.
Who classifies music based on vocals anyway? They are irrelevant...it's about the music here. In Flames are a heavy metal band these days, they do use raspy vocals, but that doesn't make them death metal at all.
Yes, CoB's tone is slightly heavier, and yes they do have black metallish vocals, hence, and I think you are all missing the first term here, "blackened" power metal.