I generally stream music to check it out. If I like it enough, I purchase it, in some form. Not because I MUST have a copy, but to support the artist.
But all of the people acting as if owning a collection of hundreds, if not thousands of CDs is no big deal have obviously never had to move overseas and fit all their life's possessions for a good length of time into a few suitcases and maybe a box or two sent by mail. Just because I'm not willing to spend hundreds of dollars to have huge boxes of hard copies of albums complete with their packaging shipped around the world, when I can fit it all onto a hard drive that's several hundred grams, doesn't mean I'm not passionate about music. It means I'm not an idiot.
In fact, even though I still make the effort to buy quite a few CDs, most of the albums I have bought as CDs in the last three or four years have either lost their cases along the way, or (in the case of the stuff I didn't like so much) I've just thrown the CD and everything away once uploading it to my laptop, iPod and hard drive. A baggage allowance is a baggage allowance, and the post charges by weight and dimensions, and you have to prioritise.
Also, two of my favourite bands both offer most of their albums as downloads directly from their websites, in 320kbps and in FLAC. It makes being a fan of them a much cosier affair.