I think I have some of this as well.
I just like to own things sometimes. It makes me feel good to get stuff in the mail and to just know I have it I guess. It happens when I'm bored or lonely or sad, then I start looking at ebay, etc and find something for me to buy.
I've been doing better with this, and even ended up selling some of my crap on ebay in order to clear out some of what I consider to be junk (just stuff I don't use, trying to simplify my life).
All I can say is maybe if you use these things you wont feel as bad, and maybe put a spending limit on it. Another option is to resell the stuff you don't want on ebay and get some of the money back - that is, if the amount of stuff you have is bothering you like it was me.