I would put it in this order for me:

50% Content
30% Gameplay
15% Graphics
5% Music

If the content is bad it does not matter how good anything else is. The game has to draw you in with a well developed story, the game has to have content for all play styles, and the game has to have enough content that you cannot finish it before they add more.

Gameplay: The controls should make sense, things should be developed for ease of use for the players. If something is cumbersome it becomes the focus instead of the content you are playing through. The battle system should flow, should be engaging. Bad gameplay will ruin a game with awesome content/story.

Graphics: If the game looks like crap I do not feel I should have to pay for it. It is one of my main problem with cartoony or Stylized (which apparently what they call crap graphics in the industry these days) mmos. I just feel like I am playing something from a past era, something that should not be released in this era. Some people do not mind, but a mmo with horrible or cartoony graphics will make me walk the other way unless it is just ungodly good (which non have been in my eyes yet). Graphics does not make a good game, but it does make a subpar one.

Music: Music draws you in the first few times, then you end up muting the game or talking on TS and not paying attention. A crap score can be a negative, but a great score will not make the game.