adventure_al said:
and they are legal as long as I don't download anything which is copyright, correct?
Depends on where you are, but mostly, yeah.
I find LimeWire rubbish mostly, too much fake files and such. Only good for mainstream music, but since that's copyrighted material it's really not something worth trying if you wish to be a "good boy".
eMule and its variants employ a lot of files and you're bound to find the thing you're looking for. However your accessibility to the files is mostly in conjuction to your own shares. I'm personally not comfortable with that.
Torrents are good for bigger stuff and my personal favorite, because you only share the thing you're downloading. The downside is accessibility by popularity. Also, apart from people who make indie films and like to mess around with alternate OS distros, I've still to hear about a torrent user who's not using the method for something questionable.
If you're simply looking to move a specific file from user to another and not looking for what other people boldy have put on display, a standard FTP client on both ends will do the job. Safe and discreet.
So that's pretty much it. I'm not going to go into further details esp. concerning the three first methods, since I'm a big fan of people finding out about stuff like this themselves. Simply because most of the time people will utilize their newly-found talents in a quest for quick entertainment in the grey area.