For years I was an amateur dealer of vintage guitars and amps. Certain items such as the higher end clean original models (generally 60's or earlier) Fender, Gibson, Martin, etc. pieces typically commanded many times more than what they originally sold for and continued to sharply rise in value. Eventually the supply dried up due to an over abundance of dealers and collectors. Another of my hobbies is motorcycling. I bought a new Harley Davidson Fatboy 2 years ago at MSRP and realistically I could probably sell it now for what I paid for it new. The supply and demand is still so out of balance with Harley's that there continues to be waiting lists at some dealerships despite a troubled economy.
Other hobbies with these economics?
Audio seems to have an interesting set of economics for the consumer. Items depreciate substantially the minute they "drive off the lot", but remain just as "valuable" for many, many years in most cases. With proper care, these components retain basically 100% of their performance and usefulness, even with daily use. Compared to autos, computers, boats, etc., a well-cared-for used audio component is just as valuable, but much cheaper, than a new copy of the same thing.
Are there other hobbies where this relationship holds up?