Well, let's play devil's defence lawyer here.
1. It's just a tool, what you choose to download with it is your business.
2. There are actually proper software distributions etc that use torrents as a way to get new versions out without killing their server bandwidth allowance. Seen linux distros do it for example. People who have made their own low budget movies as well, or small time music labels doing promotion. For a start, I've downloaded a good few creative commons albums LEGITIMATELY - Tryad, Rhyme Torrents (the clue's in the name) and their associates, etc.
Some of them have actually opened me up to artists I would never have heard of before - which is an argument I've long held with music downloading way before above-board services like iTunes etc came along and actually paid attention to that point. (They also set their prices at ludicrously high levels, but at least they listened in SOME way) ... In fact, if someone can tell me if Milk Plus HAS actually properly released his album yet, and where I can get hold of it, I'd be grateful, because it was supposed to be out around October, but I've still only got my torrented copy and no idea where to put in my order.
3. Slightly more grey area but I believe still under fair use: I work somewhere with an educational record-tv-shows-off-the-air license which we make great use of. However, some of our stuff was recorded back in the day when the guy doing it was taking analogue broadcasts onto VHS, and has since transferred that recording to DVD. In particular of late, one very popular, but specialist documentary about the actual work that goes into making movies, which was even recorded off the late night "accessible" broadcasts, with a hardcoded overlaid signer. In short, it looks like ass, and the DVD it's on is scratched to shit, notwithstanding it's a complete pain to convert DVDs to a format that can be held on a central media server on campus.
Also this programme is repeated like, never (maybe once a year or less, hidden very deep in the schedules), even on its current host channel which specialises in docs and meta-media stuff, so getting it in a hurry - which I needed to - either by making a fresh digital-broadcast-to-DVDR or downloaded from said broadcast company's own online service (anything over 7 days old = gone) was not an option. The copyright owners, for reasons best known to themselves, have chosen not to make a DVD for the region I'm in, or even release the other-region copy on my market for those who can hack their players to be region-free (god only knows why, they'd make LOADS from sales to students and college libraries for a simple act of doing standards conversion and pressing a few discs with a different label).
I go home, hop on somewhere like ISOhunt, throw the .torrent link into my copy of mutorrent, let it run overnight, by the time I'm halfway done sleeping I have a pristine, already properly de-interlaced etc DivX rip of the DVD sat on my hard disk, ready to drop on a USB stick and take to work. It's pretty much what I would have had to do to it anyway to make it more compatible here (couple hours work to get it "right", even if we HAD a copy of it and could sacrifice a DVD drive to get locked into the wrong region), and as legal as getting it off air with our normal arrangement... just without having to wait around for 18 months for a repeat, then remembering to set up the recorder for three o'clock in the friggin morning and trusting that the thing will do what it should/the schedules haven't changed.
Similarly I have some old CDs that I previously ripped to MP3 ... the hard disk said MP3s was on got stolen, my optical backups turned out to be on rather poor media, and the secondary disk I had previously backed THOSE up onto got damaged (yeah ... I know ... I'm now acting SUPER paranoid about my data these days). Plus those CDs have since suffered rather bad disc-rot, and even if I was prepared to pay more of my own money again to the manufacturer to deal with a penny-pinching mistake THEY made, some of them are rather rare and hard to physically get hold of (either limited run, or have since been superceded by horrendously amplitude over-compressed "remastered" versions with none of the originals available anywhere, etc). I already own the damn thing, so, off to the torrents to find sources which contain my missing tracks to patch into my own "remaster" - a copy of said mp3 collection with someone else's rip of the physical, legit disc patched into the hole in my rip of the physical, legit disc. And if said mp3s are good enough quality, maybe even replace my older, lower fidelity ones outright... if they're really good, use them to make a "working copy" of the ruined original, to play on the non-mp3-compatible kitchen boombox or whatever.
(the people I download from here being the equivalent of a friend with similar tastes from whom I may have taped or even duplicated a working copy of the CD(/LP?) from in times past ... and those who leech from me during this, or in the time after whilst I let the ratio crest beyond 1.00 so I'm not being an asshole, being friends who may have taped/duped FROM me; given the nature of the video, in fact, I let that hit about 5~6-to-1 because, although the service is anonymous both in terms of name (beyond an IP) or intent (beyond "getting that data") I bet many of them will be people in the same boat. It's not something you'd download and watch with popcorn and a load of friends, let's say, and if you were too broke to buy you'd at least reasonably expect your college library to have a copy you could either borrow on a short-term loan, or watch in the viewing room...)
4. Besides such arguably fair use stuff, the whole issue of where the line is drawn on piracy is a controvertial and hotly debated one. As these forums officially disallow any outright advocacy of piracy, all I'll say on that is... it's not universally agreed that those making the rules here are doing so correctly, or with anyone's best interests at heart besides either their own, or those who have them effectively in their pocket. I'm remaining utterly neutral for the purposes of this post; but as noted above, I've found plenty of legit or arguably legit reasons to use torrents, so I wouldn't want to be broad-brush painted as a heartless thief of intellectual property just because I use the same tools, just as a slim jim can be used by a breakdown service to get you into your car if you leave the keys inside, so it'd be nonsensical to arrest someone simply for owning one. Only if you catch them directly in the act of stealing someone's car with it should you take action. (And in this case, you have to imagine that when they use said slim-jim, a second copy of that car appears, and the original owner loses nothing - the manufacturer does, but what then if the thief argues that they lack the funds to have bought it anyway, and what meagre cash they have is actually spent legitimately?)
OK, that's the half hour I was having to wait for someone to finish in a lecture room filled up... laters.