Personally, I think there is a difference between pirating old games and pirating new games. There are a lot of games that simply aren't available anymore. Games that you'd HAVE to buy used because there is no longer production. For these games, pirate them. Go for it. Because, at that point, it's either pirate the game and play it or don't play it at all.
However, for new games I think it's different. These are games that are still in production. Games that you could purchase from a variety of places, and may even go on sale. When you buy these games the money goes to the publisher and the developer, and even helps the likelihood of sequels. For these games, I just don't really think there is an excuse to pirate. Not even in a "what if I don't like it" way. If you don't like it you can sell it on Ebay, Amazon, Gamestop, etc.
Piracy affects everybody. Publishers put on anti-piracy measures which piss off loyal customers. Either that or they don't retain enough in profits to warrant making sequels to games.
Now, this being said, I do think that more publishers should allow more demo's of their games.
