I don't tend to rewatch things often, but I've done Lynch's entire filmography I think at least 3 times, and I've rewatched Twin Peaks over 3 times. so I've seen Fire Walk With Me a lot of times.
It's also probably the movie I've spent the most time thinking about, especially in the last couple years since it's so deeply connected to the new series. I watched all the bonus features on the Bluray. I've even watched the spin off film The Missing Pieces multiple times.
I've always enjoyed it, never gotten sick of it, always notice something new, and still get emotionally affected by it. So I guess that means it's my favourite movie.