Listening to: Nothing.
When I was growing up, I watched X-Men whenever it came on. Eventually, it turned into this weird schedule of episodes that played out of order. Even further down the line, I ended up only catching it occasionally where the episode that showed every single time was Professor X and Magneto walking around in the Savage Land.
Anyway, from what I remember from the original series, the intro was quite cool. I used to think to myself, "how come the rest of the show doesn't look this good?" As I aged and became more "norant" (the opposite of ignorant), I learned the obvious: it would have cost too much.
Then, today, I caught the introduction made specifically for the Japanese audiences. Which one do you like better?
Related Link: X-Men - Volume 1