I bought a used 2000 Concours in 2009 with 24k on the clock. It just turned 78k about 2 months ago (I've since bought a Concours 14, so riding that mostly), and in that time, I believe I've spent a grand total of $1200 on maintenance and repairs (not including tyres, which I change probably too often.)
It's one of the simplest bikes to maintain that I can think of, overall. The new C14 is quite a bit more involved, but it's also new, and hasn't had 2 shitheaded previous owners to screw it up...
2000 Concours - Gone, but not forgotten.
2012 Concours 14 - Concours 2.0