Hi all,
BitTorrent and the use of torrents can be used for legal purposes, so discussing BitTorrent clients and which ones you use is fine. Also tools like YouTube downloading tools is ok as they are simply tools... it's up to you how you use them. Please just do not discuss using them for illegal purposes (ie. linking to specific torrent links for warez or illegal content, or talking about how extremely happy you are now that your life is complete from downloading the latest Lady Gaga song off YouTube).
On campus students use software called
DC++
To add to the discussion on music services, there are streaming services out there that let you play music without downloading anything, and can sync to your mobile device. Services such as GrooveShark, or Rdio.
If you're looking for a really affordable legal music streaming service I highly suggest checking out
Rdio, for just $5/mo you can stream an unlimited number of songs, build playlists, find recommended songs (it learns from your music collection your taste, etc), and you can also search and browse top charts and other users' playlists. So for example, if you're wanting to make a workout playlist you can search the word 'workout' and hundreds of playlists from other users will appear that you can stream and play right away, subscribe to for updates, or add to your own collection.
For an extra 5 bucks ($10/mo) you can get the mobile addon which lets you stream music, playlists, and access all the same features on your smartphone. You can also sync songs offline on your phone so you dont use your data plan (ie. you turn on syncing over wifi while you're at home and your phone will detect new songs you've added via the website and sync them to your phone to play offline).