Used games. Why? Well, both give no money to the developer, of course. But the difference between pirates and used game buyers is that the used game buyers definitely had the intent to purchase the game. To use a hypothetical but common situation, a retailer can persuade the potential buyer to buy a used version, and what would have been money in the developer's pocket goes to the retailer instead.
Furthermore, people who trade in games don't necessarily then buy a new game with their money (this is brought up quite a bit as an argument in favor of used games); indeed, many just go on to buy used games, and a cycle is born.
A lot of pirates never intended to buy the game in the first place (or, at least, would never buy it fully priced), so it's not necessarily lost money; you can't prove that there was ever a potential sale there. Some did intend to buy, but then again, some pirates also go on to buy a game after they've pirated it (yes, that's actually not very common and people use that excuse for justification a lot, but it does happen).
So I say the secondhand market, to some degree, hurts developers more. That said, they're both pretty awful and I despise piracy in general.
In memory of Topless Avatars Pertaining to Hotness and Titilation (TAPTHAT).
3DS friend code: 5155 - 2983 - 3034
