I 2nd pessimism's post. Some good recs there. I'd say start off with the more mainstream bands that everyone seems to like before delving deeper into the heavier more underground bands though. Definitely try to appreciate the roots of metal with Black Sabbath, Iron Maiden, Judas Priest etc.
If you want to jump into heavy stuff straight away, I know I started off with Decapitated, Behemoth and Dark Tranquility.