It depends on the game. Most titles I think its a minor thing but some games, such as Legend of Zelda need to have excellent music. I mean, can you imagine OoT without good music. Whereas GT, Fable or Gears don't need especially good music, it just needs to be sufficient.

Music is very important to me b/c it gives the game soul and feeling to the gamer.

Until this gen I barely used to play games with the sound. Just used to listen to music while playing. Now I play with the sound cause the Wii remote has audio and would be distracting from my music. Still I don't really pay attention to the music in game so I would say it is 100% unimportant to me.

It is probably the thing that makes me link to a game, like, forever! An excellent soundtrack will always make me want to replay a game. That's why I still play the old 8-bit Konami/Capcom classics (also for the gameplay)! The last game I have in mind that has awesome music is The Last Remnant. The gameplay gets repetitive, but man, the music is too great! o_O

Just to tell you how game music affects my everyday life... Just for fun, I mostly do this: Make a remix in your mind to a game's soundtrack. I just love video game music. It's funny when you play a new game for the first time and you're expecting the music to sound something like what you're singing in your head, and then it's exactly the same! You know it's an excellent soundtrack when it happens (see: Bionic Commando Rearmed). ;)

I even made a thread about video game music remixes because I love it so much. Check it out: http://www.vgchartz.com/forum/thread.php?id=32671

For me it's Gameplay >>Music >> Length >> Graphics.

at first, no. but then when i played super metroid (especially in the water, and sandy area) that’s when i first noticed how important background music is. i actually felt a little more involved in the game.

  it’s crazy ‘cuz i was thinking and imagining how samus could/would feel:

a bounty hunter, in a distant world all alone..

Very important.

and to add, i agree, Zelda music is always awesome. OoT was all around great, and TP has cool music. i also appreciated how nintendo added the day/night feature, and how music and the lighting transitions you into different settings of the areas

I don't really notice music in games. The only game I even remember with a decent soundtrack was The world ends with you.

Okami's sound really gets you involved in the game.  Sets the mood, and really makes you feel like you are in the game.  I like just about everything in that game, but the sound sets it apart!