My passenger one has an annoying intermittent rattle, which is coming from inside the seat. I made sure it was solidly locked into position, and held the adjustment bar while I was driving to make sure that wasn't rattling around.
It was there for a month, went away for a couple months, and just came back yesterday. It probably can't be fixed without taking the seat apart, which is more trouble that I want to go to, so I may just have to live with it.
If you're listening to music you can't really hear it, and I am almost always listening to music when I'm in the car.
Edit- the noise turned out to probably be the garage door opener.