Testament is really good, Old Exodus kicks ass, Old Slayer, Old Sepultura, Old Anthrax (the new stuff is good too)
I wouldn't call Pantera thrash. They have some elements of thrash but they are more straight-up heavy metal oriented. And no one can deny that they are partially responsible for nu-metal.
I tried Kreator, and thought it was pretty boring...saw The Haunted live...nothing special.