I work with computer and such for a living, internet and programming work. So here's my two cents.
1.Don't be too scared, Honestly, if your gonna use bit torrent, go ahead and use it, wanna know what ISP's see transferring when you are downloading, a bunch of random snippets of data and garbled packets, All that they can do is honestly tell if your USING bit torrent, not what your downloading. They are able to throttle you, slow down your transfers. Guess what, they have no case about what your downloading, bit torrent is being used as a commercial way to transfer podcasts, software, and videos. And now there some bit technology that can't be throttled, it looks like normal data.
2. If you have without a doubt your gonna get busted, smash the hard drive. First reformat it, then reformat it, then take it outback with a baseball bat, hammer, flame thrower whatever your heart desires, and smash that thing. Next up, set your router to a dynamic ip address, make it change every 10 minutes, drives ISP's Crazy. I know its sad, but make a backup. and put it in lockbox or something. The only proof they would have is that, there was A.) Bit torrent being used B.) Any Mp3 player you own with the files is proof, they are the same files you had on the original hard drive.
3. Limewire is now the king, Ares, Kazaa, Napster, Bearshare all got nailed, but limewire is still going. It doesnt help everyone using it if you turn off sharing, but unfortunately we have to so do it. Now files being transferred this way is a direct transfer, it takes the pieces in line, in order. so they can be identified. now this is basically a no brainer, don't share, Let our canadian friend share it to us, they can't be touched,
4. Not all isp's will give up your logs, some contractually will not. But they have been known to do so here and there, you get a notice saying we have logs, you ask to see the logs, even if you can't understand what they mean, ask to see them, Their is a chance they are bluffing, a good chance. The most proof they have, is finding the data and you admitting to it. Remember the biggest problem they have is sharing, so seed for a little bit on bit torrent, then kill it.
5. If the RIAA says they were "in" your computer at any time, sue the shit out of them for computer fraud. Thats plain old hacking, even if they bluffing go for it. Look what happened when they went into the pirates bay servers, The riaa and mpaa now have a huge lawsuit on them for it, and it isn't looking good they will most likely get sabotage.
im not saying steal music, movies, games, and etc. im just saying just in case, No one has the right to the data on your computer without a warrant remember