I will try to be as subjective as I can and it won't include only my favorite genres as I will try to include albums from all Metal sub-genres because I think it's important to get exposed to all kinds of metal so that a person may create a good taste in Metal music. (Might include more than 1 album per band).
Note:
1- I don't care if an album was responsible for the birth of metal, if I don't like it then I won't put in the list.
2- If you have any suggestions, I'll be more than glad to take them into consideration
3- The list is in chronological order and not in the order of preference
