I have got an Ibanez RG, and a Marshall MG30DFX, both very cool indeed :D. When learning songs by slayer and other such heavy metal bands with a tuning of half a step down from E i dont get the heavy metal sound i want. I have set amp up following the manual that came with it for Heavy Metal, which sounds better but still not amazingly heavy metal like :( So i have decided to buy a Distortion Pedal OR an Overdrive Pedal, but i dont know which one of the two will give the best heavy metal thrash sound!?! :S and there are so many out there im baffled as to which to buy.

So my Knowledgeable Chums, have you any pedals to suggest, or can somebody at least tell me which is best for heavy metal, overdrive or distortion pedals.

:D thank you!