ROFL, your story is the same as mine. I listened to rap my whole life and now I've been listening to Metal for 3 years too, but System of a Down made me a Metal head and then Slipknot was my 2nd favorite band.
Bands: I mostly listen to the same ones as you but I have a few really good ones that you don't have:
Mushroomhead=Nu Metal, Alternative Metal
Megadeth=Alternative Metal
Lamb of God=Metalcore
All that Remains=Metalcore<---Awesome band
Rage Against the Machine=Rapcore/Rapmetal
Avenged Sevenfold=Hard Rock/Alternative Metal
Shadows Fall=Metalcore(I think they're Metalcore, not sure)
Mudvayne=Alternative Metal
Alice in Chains=Alternative Rock
Drist=Alternative Rock
Coheed and Cambria=Alternative Rock
Black Sabbath= Alternative Rock/Alternative Metal
Pantera=Alternative Metal
Paramore= Alternative Rock<---girl vocals
Flyleaf= Alternative Metal<---Girl vocals
Metallica=Alternative Metal
Led Zeppelin=Alt. Metal
Iron Maiden=Alt. Metal
Children of Bodom=Alt. Metal
Dethklok=Not sure, but it's some type of Metal
As I Lay Dying= Heavy Metal
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