This is a generational question. Whatever songs you grew up with will never get old. Then, when you do get old, you'll have a bunch of young strapping lads around you complaining that your music is shit, and you'll be complaining that THEIR music is shit. If you're smart enough, you will realize the power of opinion. That reality is perception, life is what you make it, and you have chosen everything that has ever happened to you.
But, to answer this question;
Tool is my shit, and I don't think it will ever get old.