Describe the way you use file sharing

I've had this debate too many times, and wanted to get an opinion from others. I know this is a totally unobjective crowd on the subject, but where else can i ask the question? Anyway, here it goes:

With file sharing sites, the ones Like Kazaa and Limewire... etc, do you download songs to:

1) prevent yourself from having to buy the cd if the rip is a good quality rip
2) demo a cd before you buy, but definitly buy the cd; or look for new artists before you buy
3) sometimes buy the cd and sometimes don't.

If you fall into category #2, and you find a musician you really liked, would you then be encouraged to buy more of that musician's cds based on your downloads?
I only use these sharing services to acquire rare songs that are not readily available by other means (e.g., the cd is out of print, bootlegs, etc). I'll also download new/previously unreleased songs that are only available on otherwise useless greatest hits albums --I consider that fighting fire with fire.

Otherwise, I will always buy the cd.
I've heard it all..."I only download the two songs that are worthwhile, why buy the CD?" and my favourite "everyone does it, the recording industry has to adapt". Don't pay artists; they will find other ways to support themselves, it's not too tough to figure out. I'll climb off my soapbox. On a related note have you noticed the huge jump in CD prices lately? No wonder people steal the music. Recording companies are their own worst enemy.
Out side of college radio, it's the only way for me to hear new stuff. I guess I tend to fall into #2. Since the rips are free, you get what you pay for (i.e., the rip quality is generally poor). If it's worth buying the music, I'll buy it. Else, I forward it to my brother. I know he likes free music without having to pay for it (he falls into #1). But I've been known to keep a few things around as background music on my $20 computer speakers.
I've used to it for the following:

1.) to get prerelease listens to my favorite artists. Peter Gabriel - Up was on WinMX about 3 weeks before it was released. The tracks on file sharing also included a very good song that was available on the promo disc, but did not make it to the retail release. Had I not used file sharing, I would have missed out on that track. I justify grabbing the prerelease stuff only because I know I'm going to buy the CD once it's avaialble.
2.) To get copies of performances that take place on TV shows and at radio station appearances. I figure these are really public domain since they went out over the airwaves. Lots of times these are acoustic versions that might not be heard anywhere else. In this category, I also have lots of interviews that many times are streamed on the web, but if someone grabs and encodes them, I can catch them later.
3.) Sample artists that friends refer me to. If I download a few songs and like them, I will buy the album. If I don't like it, it gets deleted off my hard drive. Life is too short to have bad music taking up space!
4.) bootlegs and live shows - these I'd pay for if the labels would bother to release them for my favorite artists. Pearl Jam has the right idea I think in officially releasing an entire tour, show by show.
5.) one hit complilations - OK, here is where I am in blatent violation of copyright. I have 2 or 3 CD's I've created for my wife that have singles she really likes to listen to in the car, but there is no way I would buy those CD's for one song. Fell free to blast me on this, I know it's the kind of things the labels hate, but I'm not going to put this on them with the argument "if music was better, I'd buy it...". Nor will I justify this because I've bought $20k in legitimate over the counter music. It's a very small portion of the file sharing I do, but I know it's wrong. Just being honest here...

I do what Curbach does and agree with Jeffloistarca. Has anyone seen the class action lawsuit against the music industry accusing them of colllusion to set cd prices? I signed up for any settlements. I hope its not a scam. Anyway Ive bought a lot of cds for artists Ive downloaded, as well as taking stuff because its out of print. Its also handy for finding stuff you might hear in a TV commercial or store.