I was thinking this morning, what are the "cant miss" sets out there as far as resell potential? This is mainly for the dealers/auctioneer guys to draw apon their experience, but what set do you hate to see walk in the door because you know it wont sell very easily,and what set gets you excited because you know people will line up to bid/buy? Lets consider sets from late 1800's through 1970, all sports, graded/not graded.
To summarize,
What sets can you "sell all day",and what sets can you not get rid of easily?