come on, guys! stop the violence!
Novembers doom is a doom metal band. Very nice, indeed.
GR is not the debut album. But it's been the most sold and publicated. It's OK you want to learn more about metal, it's a very cool genre. You should start with some thrash or power, before listening to black, death, or even prog metal. First get used to the sound with some very melodious songs. If you like Opeth, you should listen to Damnation, Deliverance, and Blackwater Park before going into Orchid or Morningrise (perhaps, "To Bid You Farewell" is a nice song to start with).
Maybe you should listen to "The Drapery Falls" or "Master's Apprentices" Both of the have a heavy part and a mellow part.
Here's a secret: The song that made me into metal was "Face of Melinda". But the first metal album I really loved was Last Fair Deal Gone Down-Katatonia.
Welcome to the forum.