[quote name='aunt beast']so what would you guess might appreciate the most that is available right now? i'm just curious - not planning on going into the reselling business myself.
medieval market village seems like a good bet at a reasonable outlay.[/QUOTE]
Yeah, I think Jay is right on the money with his response. Ironically, I actually picked up Market Village as a LEGO "investment" last year, thinking it would appreciate and I swear LEGO doubled the number of places that carried it and it has remained at $100 or less online. I have no doubt that Market Village will someday be sought after because of the uniqueness of the set but I don't think it will be really really valuable just because it has had a substantial run. Here are some of the criteria I would use when looking at sets that are good investments -
1. Does it appear as "Hard to Find" on the LEGO website - normally these are either LEGO store exclusives or retailer specific exclusives, so there's a better bet it will be harder to find after it stops being produced.
2. Is there a nostalgia factor or wow factor - LEGO fans love certain types of sets and themes, the key is to figure out which sets will be nostalgic (batman) but not overproduced and oversold. If it's also just crazy big or expensive, it will probably be worth more too (Death Star) just because kids will grow up seeing it but not owning it ... and guess who wants to buy it when they finally get disposable income in 20 years.
3. Does it appeal to adults - Modular buildings are hot, they sport great design and are highly collectible because they can be purchased as a series that grows over time and allows you to build a city block. Even crummy ones like the fake-modular set that came out around the same time as Cafe Corner but wasn't official has risen in value substantially. The creator houses are great too, and less expensive ... however, those will never be worth as much as the more expensive sets simply because of the initial cost.
4. Lastly ... rare minifigures. This rule applies more to the pre-magnet era of LEGO, but if it has some crazy mini figure you can't get anywhere else, chances are it will be worth alot (every Batman set ... Jabba's Sail Barge as 2 examples)
If I had to throw out a set that will be worth a lot of money in the future (besides Green Grocer), I'm going to skip Fire Brigade (which isn't bad but just isn't WoW) and say you should pick up Grand Emporium. That set will be worth tons once it goes out of production ... mark my words, it's probably the most detailed modular out and it's already hard to find now, while in production.