Are you talking about Hi-Fi speakers which require an amplifier, or pc speakers/active speakers with a built in amplifier?
If you mean Hi-Fi speakers which require an amplifier, for LOUD listening of metal, i would recommend Cerwin Vega speakers. They are loud and aggressive. Cerwin Vega are well known for making stage speakers and such as well...
And because of thier nature, they tend to make metal sound nice and 'full' because they are not audiophile grade speakers, so you do not notice so many of the recording imperfections typically associated with metal...
In that price range there are the VE-5M's (might be a tad difficult to find online)
For desktop speakers, it is probably best to wait for a response from someone with more experience of desktop speakers, though i would recommend logitech, corsair or edifier branded PC speakers.
And remember that wattage does not = volume.