Late to the thread. Read (perhaps too skimmily) through it. While generally accepting the principles behind "Pirating is Ok if... <various reasons>", I don't think it has been pointed out that by ('legitimately') pirating through torrents you are simultaneously assisting those who are outragously pirating (without the same good reasons) their games. Possibly by keeping the seed going when the OP drops out. I don't know if that matters to many people, but I'm sure it's a charge that a particularly litigious IP owner might lay against you, even if they accepted that you had a scratched disk/whatever and were just getting your rightful use out of a paid-for game.
Let's go personal on this issue, though. I've got many different thoughts about pirating. Films that disappear from the cinema or programmes broadcast but which fall off the broadcaster's schedule/on-line player before I can see them (that I would never want to 'own' as a DVD) I could see downloading (for now ignoring the above caveat about assisting others), but I can see several monetary imbalances there. I know from viewing (other people's) 'acquisitions' that Cam versions of a film are often rubbish, and production-leak versions are laughable, so if I've missed the cinema release then I'm really waiting for the DVD release, anyway, for to pirate a ripped version. By then is it even worth it?
I have no sympathies with big bullying and overcharging companies. Not sure if I whether I could hurt them in the wallet in this way. Even less sure whether I should try (only partly because of the possibility that they'd bite back). But I have grown somewhat wary of Steam (through experiences-by-proxy, with friends having difficulties with legitimate purchaces, back in the early days) and when I do scan the local computer store shelves for games that might tempt me (but never do), I immediately reject any with a Steam bit on the obverse label. Never tempted to 'correct' that situation by downloading, though.
Actually, for software, I think most of my reticence is of the "is it real? is it safe?" flavour. Whether already necessarily DRM-broken or not, can I truly trust J. Random Game downloaded? I've dabbled with Abandonware in the past (already languishing on such sites for a while, anything nasty on the older stuff will generally be well within the detection radius of my standard protective shields, if it hadn't already been revoked and/or cleaned after prior complaints), but I'm not certain I'd ever pirate current releases, even if I were so inclined as to save myself the wonga and footleather of getting it 'for real'.
I remember playing the full Doom (original Doom, no numerical suffices or wordy prefixes) back in the day, someone having handily left a version (easily copyable back to 3.5" diskettes, with a spanned .ZIP, I'm fairly sure) on a University computer, when the only legitimate version I was entitled to was the shareware "first episode only" version. Ideally I would have bought myself the full game later on, as a belated payment. By the time I was in that position it was already Doom II that was out, and I was (properly) buying all kinds of other things left right and centre. Carmageddon. Duke Nukem 3D. Elite II. Battletank. Games like that (although I might be out by a few years, if you cared to actually check the chronologies). Included some I really oughtn't not to have bought because they were rubbish, and (actually) I wouldn't know either way whether I even ever added to ID Studios'/whoever's coffers as a more indirect recompense.
Right now, what's my big thing? Well, DF (no issues with piracy, and donations to be given as/when I find it convenient to do so). Kerbal Space Programme (the free version, ditto[1]). I dabbled with Minecraft a bit, before I found that the copy I'd been given wasn't actually shareware (and playing single-player might be thought akin to masturbation, although you ought to have seen some of the things I tossed offup while I was engrossed with it!). That's about it, given the amount of time I spend developing practical things instead, apart from some odd Freemium web-based games that I don't partake in the paid-for features of. And those three prior examples are all games that I really do want to support because their respective developers (at least when the question first came up) weren't "Big Bad Bullies". So really I should not want to try to defraud the two (DF not included, because this doesn't apply) that really need paying to use the latest and greatest versions, so if I had more free time I'd probably be paying for these things, and still avoiding Steam due to the aforementioned prejudice (but not making up for it with any sneaky side-steps).
So, that's me.
Caveat Emptor, was my original point. Or whatever the equivalent is for a non-buyer. But it looks like I've gone into a lot of (mostly hypothetical) personal approaches to the problem as well.
[1] Although I did mention the game to a colleague who may have gotten himself the latest version. With or without paying. I shall distance myself from that, but it may tarnish any moral shield I'm wielding.