Found a 2004 BMW Z4 with 263K miles on craiglist today
Body still looks good except for the missing fender turn signals. I guess these cars are mechanically reliable.
http://sfbay.craigslist.org/nby/cto/5188680377.html
I myself just got a 2003 with only 104K miles that I am planning to keep for at least 7-10 years.
I intended to drive it only on the weekends but these cars are so much fun to drive that I been driving it almost daily.