Yeah, just found the digg entry and I'm reposting the "law" that is stated. I put quotations around law cuz I'm not sure if it's accurate, but if you repeat it verbatim you'd still have the person running the store give in.
Here's the law from the UK:
You have the right to your goods that are fit for the purpose for which they are sold, free of defect, and this is for a 'reasonable' period of time (depends on the item you bought). If they're not, you have the right to a replacement, repair or refund (of your choice, not the store's). Store policy cannot override this law, and mentioning the 'sales of goods act' is usually a good way to get your way.
Obviously this only applies if you've not damaged it yourself, and the defects were there when purchased (though they don't need to have been apparent at time of purchase, they might not surface till days or weeks later).
If they give a refund, it's illegal to charge a 'restocking fee' or anything like that. Similarly, you don't have to accept store vouchers, and they can't force you to take them.
If you bought something that you simply don't like then all this doesn't apply either.
If you bought it over the internet, by phone or by post, then you have 7 days to check the goods over (different act to the one above). If you don't want them (for any reason, you don't have to say), you can return them for a full refund. The cost of postage may be up to you, I can't remember exactly.
A lot of stores think they over-counter signs (like "we don't give refunds") are above the law - they're not. Also, items in sales or reduced are subject to the same laws, even if they say "no refunds" or "as seen". If any defects are clearly marked then you can't use those to get a refund/replacement/repair as you knew about them at the time you bought them.
And then the clause from a US law:
According to the United States Consumer Protection Act Section 13 of Category 2 (Sale of Products and Provision of Services):
"In case of any defect, flaw, or imperfection on a product, upon request and by option of the consumer the trader is obliged to replace the defective/flawed product[...], return the amount of money paid and compensate for the actual reasonable cost of return of such defective/flawed product, or repair the defect at the trader's expense. [...] If the consumer detects a hidden defect or flaw [not able to be seen at time of purchase],the request should be submitted within eight days [...].