If you are buying purely for investment purposes then my advise would always be stick to buying Gold. Seriously that would be my advise, but nobody is in any dought that the recession is making selling anything very hard indeed. Yes the very rich will continue to purchase luxury goods, but the average man simply cannot afford to do so when the price of basics is going through the roof every day, suddenly even $100 seems a lot to pay for a pair of jeans. Expendable incomes have all but vanished and a lack of credit means people have to live to their means, ie what they earn not what they can borrow. Regards RMC and Yoropiko, I have no dought they will increase in value in the coming years as fewer and fewer pairs survive. Me personally I buy them because I like them, if they are a worthless pile of denim in 20 years then so be it I really am not bothered in the slightest. Whatever anybodies perception of my collection in future I'll have the knowledge that I possess items so rare they are no longer attainable no matter how much cash you have in the bank.
Look at the NB Yoropiko Dragon sets for example, you could be worth millions but all that cash wont find you an NB set easily, thats exclusivity in my mind.
I know of a massive sneaker collector who has over 300 pairs of mint rare shoes and he just cant shift them, many are worth in excess of £2K but best he could get is £500 max. so he is just gonna sit tight and keep them rather than let them go for silly money.
The market will return eventually, until then you just gotta sit it out and wait.