I'm calling BS on this one. Just because it has a price tag for $8,000 doesn't mean that people are willing to purchase it for this price. In this economy, if a luxury item is selling at all, it is selling at a discount.
If you have an item that has increased almost 100% in value in 4 years, then it must fall into one of the following categories:
You either got it at an incredible discount, and it was worth much, much more when you bought it, or
It was a limited-edition model that is incredibly scarce and highly in demand, or
There is a crazy Breitling bubble and it won't be worth $8k for long.
To each his own, though. If you have the money, and a fancy watch makes you happy, then go for it. I've spent money on worse things.