Be ruthless
Dump the crap
500GB sufficient for a mere mortal.
Keep the masters though, even if they're boxed up and in storage.
You bought them for a reason, you may be in the mood again one day.
Steve.
My sentiment is that if you are going to keep the master CD in the loft, you may as well have ripped it before putting it there. I find long lost tracks get much more plays since it all went on the network.
If you really don't like something then get rid, but, one perhaps need to check purchasing methodology. Previews and samples really help these days I find.