One philosophical theme I've managed to extract from this discussion is the importance of degree
to our moral assessments. Most of the posters seem to feel that buying multiples of a given set is acceptable if the purchase is to add to a collection, and maybe one or two additional sets to sell later is OK as well. So the action itself doesn't matter, only the intent. I find this to be slippery moral ground, not anywhere near a high or low road. To use an extreme example, murder is murder, even if the purse-grabber only meant
to knock out the old lady. It's a bit disingenuous to say "some is OK, more is not" and "if it's for your collection, buy as many as you like." Just like more money, increased personal economic utility is also a form of "greed" -- and who among us would begrudge indulging our LEGO fixations?