Here are a couple of more ways to be evil, so you shouldn't do them:
Using 'vlc' (a free, open source, cross-platform video player), you can specify a youtube video URL, and it is fully capable of 'ripping' the video (and audio, or JUST the audio). So all those nice youtube links with music are easily converted down to MP3 files, which can then find their way to your portable music player.http://www.videolan.org/vlc/
Subscribe to netflix, blockbuster, or both and rip those DVDs with 'handbrake' (another free, open source, cross-platform tool that re-encodes DVD content to m4v files, playable by VLC (and therefore ANY computer), a PS3, iOS device, etc.) A single, inexpensive external 3TB USB hard drive can hold THOUSANDS of movies (though you'd want two, in order to have a back up). You may need to use a commercial 'ripper' to rip certain mickey mouse titles that are 'copy protected' (a tiny minority of DVD titles, overall). http://handbrake.fr/
The benefits to these techniques over just 'downloading' content that has been encoded by others:
1. You won't be part of a monitored torrent and targeted by copyright lawsuit squatters who participate in torrents, and trace who ends up 'sharing' it, something that happens automatically with a torrent, unless you're a 'leech'. Better privacy overall, since neither ripping technique is traceable. At least not on-line. I'm sure if you unwisely shared or resold your files on a massive scale, and managed somehow to miraculously get police attention, they could find you through standard police techniques. But the IP lawsuit trolls won't ever get you.http://venturebeat.com/2011/10/01/hurt-locker-torrent-lawsuit/
(Note: Those big 'cloud storage' solutions are a trap! If you have pirate MP3s, and you store them online, the service provider is just a court order away from narcing you out.)
2. Since you encoded it, it has NOT been encoded by someone who included a virus in an especially 'corrupted' file. Especially important to windoze users, for whom 99.99+% of all malware is written.
3. WYSIWYG. You don't spend time downloading something, only to discover it's not what it claimed to be.
4. Bandwidth, for the DVDs. If you have any kind of bandwidth limitations, the DVD rental is the way to go. If you always get your 'two at a time' DVDs from netflix, rip them, and have them right back in the mailbox again, you can get four movies a week. In a year, that's 208 movies added to your collection. If you combined netflix and blockbuster rental plans, you could easily accumulate 400~500 movies a year, for the cost of a couple of dozen DVDs.
5. If you travel, you can easily carry a hundred m4v movies on a portable computer's internal hard drive, and playing them will consume vastly less power than spinning a bulky, wobbly piece of (easily lost) polycarbonate plastic.
6. The DVD ripping is 100% perfectly LEGAL, if (and ONLY if) you own a copy of the original movie. DVD, VHS, Beta, Laser, doesn't matter. So if you have a library of DVDs (even a stupid-big one), you can rip them to a hard disk, and the kids won't get greasy fingerprints all over them, they can all stay nice and safe. Then you can store all the DVDs in a couple of cake boxes and recycle the excess packaging to make room in your house for something else. But only if you don't want to be evil.
7. One could theoretically coordinate with some close, equally evil friends and exchange the m4v files to accumulate massive libraries of movies very rapidly. After all, those kid's movies add up real quick.