I only collect things I actually want to listen to, not just for the sake of collecting. But I've been on a paring down stage, too. I've figured that I have more stuff than I can listen to for the rest of my life, which is ridiculous.
But that decision is also partly the result of ebay. On one hand, I can now find copies of things that used to take years of looking, so I'm less nervous that I'll get rid of something and never find it again if I regret the decision. The other hand is that stuff that the used CD/record store would offer .50 of $1.00 for on trade in (I'd sooner forego .50 and give a good but common album to a friend), I can sell on line and get $3 to $15 for, a big difference when multiplied by 50 or 100 items.
Still, just 50? I don't know how I'll get down below 1000. I go through the shelves to pick out things I don't really like, and I find so little.