Springfever,
It's kind of a simple decision for me - I have only one garage spot, and live in the city. It is an UNBEARABLE PITA to deal with two cars, and I've already bought a V70R to replace the truck.
Perfect world, I'd keep it until it until the wheels fell off. It's exactly how I wanted it, and is running perfectly. But its not worth it to me to keep moving it (and *gasp* park it outside!!!

), insure it, and watch it get creamed by the people in my neighborhood who think parking is a contact sport. White bumpers, and all....
I disagree that it's worth less than what I've asked, although I've lowered my price to $12k to insure a quick sale. It's worth what the market will pay, not what KBB arbitrarily sets. That said, I appreciate your opinion (not meant sarcastically at all - seriously.)
I love my ML, but it's time for it to go to someone else who will love it, too.
-Ian