What is the best HEAVY METAL speaker?

Cerwin Vega speakers and heavy metal may be the perfect match. 

I was cranking out Albert King w/ Stevie Ray Vaughan "IN SESSION" today at party volumes on my Klipsch Forte powered by a 40 watt tube amp and getting down with it.

Do the ATC 150s I sold Mettallica count? 

Brad

I've got a pair of ATC 110s and it's hard to imagine anything better for loud, amplified music.  They can play very loudly without distorting.  I doubt anything can compete with their combination of high volume, low distortion, and excellent in-room behavior. 

I also think they make a tradeoff that other companies should make.  They don't use the port to lower the -3 db bass frequency.  They let the bass roll off slowly starting at a higher frequency.  It means they don't excite room nodes as badly as a typical ported, -3db at 30 hz speaker.  It doesn't make for good marketing but practically speaking, it's better if you want top quality bass and don't want to mess with equalization.  I think it actually increases dynamics, the punch is great, and if you want more bass get a sub to fill in anything you want.  

Transient speed becomes an issue for modern metal given the tight distortion profile of the guitar intended to be percussive. The type of speaker that falls apart with funk will fall apart with this sort of metal. 

Other than that, older or more classic sounding "heavy metal" isn't much different than rock in terms of play back needs.