If you could only listen to one song for the next month, which would it be?

No song is that good.

Also, I would grow to hate whatever song it was, so I'd have qualms about choosing one of my favorite songs and ruining it.

But let's make it "a record album played in its entirety".

I'd be able to handle any of these:
http://en.wikipedia.org/wiki/Reign_in_Blood
http://en.wikipedia.org/wiki/Altars_of_Madness
http://en.wikipedia.org/wiki/Rust_in_Peace
http://en.wikipedia.org/wiki/Necroticism_%E2%80%93_Descanting_the_Insalubrious