Here's the checklist for me
Is it still in print? As in, would the original devs get the money if you bought it? If no, then it's fine. If yes, go to the next one.
Is there a highly intrusive DRM that negatively affects performance, or your ability to play it on your own time, in any situation? If yes, then it's also fine, provided you've purchased it legitimately (I consider piracy and cracking to be one and the same). If no, go to the next one.
Are the publishers shitheads who have basically bought out the company meaning that your money would only go to them, and not the actual devs? (IE THQ and STALKER or EA and most of the C&C games.) Then yes, it's fine. If not, go to the final one.
Are you going to buy it at a later date, and are only pirating it because there's either no demo, or the demo is not representative of the final product's quality? If yes, then it's fine. If not, eat shit.
Pirating just to pirate when you know you have the money, and you know you're able to buy it without it coming at the cost of other hobbies or legitimate human needs, because you just want something for free, is pretty scummy imo. There's a reason why most crackers like Razer-1911 and SKIDROW put "if you like this game, BUY IT!!!" in their installers.