Very cool. You got me thinking... It was 10 years ago this month that I, too bought my first X5. I bought it so that we'd have something safe to bring home our new baby in. We loved my mother in law's '01 E53. We were convinced we were having a boy.
Ten years later, the old 3.0 lives on next door at just north of 120K miles. It still looks good. Our little girl got the idea all on her own that she wanted to try out for competitive soccer. And I am just over 3 years and 50k miles into my '04 4.8is. My mother in law's '01 is still going strong just shy of 90k.
I don't know if I will offer the 4.8is to her as a starter car in 6 years, but I have the feeling we'll be at a turning point either way.
The E53 is great ride to have over all these years of another really great ride: Life. Let's hope the next ten years are as much fun as the last.