Newsgroups! Cheap and fast. Though the only down side is its almost impossible to get old files. Though Giganews has increased there retention to 365 days.
Best way to download i think!
Torrents are great. Though on most you will get very slow download speed. If any at all, mainly public torrents.
Private torrents can be great. Though on those sites to get those also require you to upload alot or be banned. That was near to impossible for me. Then i was on a server. If you were trying that on you home connection. Would be so bad...
Rapidshare - well this can also be great, just as long as you pay for it.
Limewire - Never. Maybe to get a few songs but thats it...