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?

Guns keep their value, especially sought after ones. Custom knives and custom pool cues also appreciate in value as well. And then there are comic books. I bought some #1 issues of Vampirella and Creepy last year. Boy I wish I still had that Spider-Man #1 I sold in 1979. I think that thing is worth about $16,000 now. Oh well.
beer steins. audiophiles always know what they have and buy and sell according to current market value. we are all happy with our sales, purchases and goosebumps. stein owners typically don't appreciate what they have because somebody somewhere gave them this thing that just requires space to store, hence they can be purchased for pennies on the dollar at the local rent-a-space antique mall, brought home and enjoyed while they appreciate. it is too bad that the black plague is responsible for the existence of the beer stein but it sure is nice to drink a polaner out of a 1k stein that you just paid 70 bucks for while sitting in front of the hi-fi.
Well, if you liken our hobby to others of similar enjoyment, then it would be those hobbies that feature "aging with grace", beauty, adjustability (tweaking), functionality, and oftentimes investment.

Those who collect postage stamps, matchbook covers, Coca-Cola bottles, etc. need not apply.

But many collect vintage motor-cycles, arms of many varieties: e.g cross-bows, alcohol dispensers: including the beer steins above and beer taps (I just missed out on a HALES tap to match my "Hales Heavy" placard...over my T8's), table-top radios (I have 30 odd from Crosbys to Lil' Pups), cast-iron farm animal lawn sprinklers from the early 1900's (these can fetch thousands!) pool tables, musical instruments of course and on and on.
I like to pick-up the odd item that will accompany my audio stuff...like 1/18 scale CART and F1 cars (Nuvolari, Clark, and Ma. Andretti cars in particular).

What other unique collectibles do Audiogoners love to keep?
I have two Japanese Samuari dolls dating back to 1956 and 1965. Both are all Porceilin with cases. I had a chance to buy a female doll made in 1912. I turned my back for a split second and it vanished.
Unreal Tournament!!!

Tweaking and learning from my home network to advance my career actually. But hey, a little UT is good for the soul.
I agree with firearms as noted above. And especially if fired no more than moderately and well cared for. Some collectors just buy to collect and NEVER fire them, but I personally can't see doing that-- I want to know more about the firearm. Good firearms actually hold their valve much better than good stereo equipment. But I understand your point about "daily use"-- stereo equipment would excel there. Cheers. Craig
I'm studying to be a lawyer on the cheap,so I can add to my already numerous friends in the Audio trade-Cyber and terrestial,it makes sense.............
Tons...my folks in Los Angeles used to drag me as a child to Southeby's(sp?) and other auction houses on weekends while they bought up all the antique treasures that LA's wealthy were dumping off during the recession. Beautiful antique persian rugs, antique furniture such as kittinger & berkey & gaye, 15th century altar frontals, 18th & 19th century china, etc etc. My mother is definitely OCD and researched everything to death. My folks 5000sf house is packed back to back in just about every room with these "treasures" and I'm sure that just about all of them have appreciated even more than the property itself. I myself, am a minimalist...I always said that I would be happy living in a museum gallery with a couch & a stereo. To me, it's all a bunch of stuff that I am afraid of having to tote through life with me.
Unreal Tournament??!!!!! No!!!!!!

QUAKE!!!!!!!!! Q3 Team Arena!!!!

Mdominick, fragging sure does make the day easier, doesn't it?

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.
Photography/Cameras. See Audiogon's sister site.
I am into the gun thing, and it works, I always make money buying and selling. Watches are on the same level, if they are pricey enough to begin with, well maintained they go up in value. To hell with cars, a loosing battle! What I don't think is a good thing to collect is all of that Nascar junk, over priced crap, and will it ever be worth more then you pay?? doubtful.