P.O.D was my shit back in middle and High School. While most people only really knew of them from their Satellite days, a lot of their albums past that were pretty solid. Self-Titled, Testify, and When Angels and Serpents Dance were all solid albums. I stopped following them shortly after Angels and Serpents, mostly because I didn't really listen hard rock/numetal after High School. They still however have a small place in my heart and I listen to them every once and a while.
Also got into Demon Hunter pretty deep while in College. Honestly, they were my gateway into the more extreme genres of metal. Especially Black metal. They are nothing close to Black Metal, but the screamed vocals and more aggressive blast beast of their early albums really helped me ease into the those more aggressive genres like BM. While they probably now call themselves a Christian group nowadays, they previously hovered in that grey area of having a more positive message in their songs, with the aggressive metal sound, all while not shoving a Christian rhetoric down your throat. Their first 5 albums or so are still great, but after that it get's a bit shakey with a only a few songs that I really enjoy.