It looks impressive, but it really ain't. Most of it is odds and ends. Some of it was given to me, and some I can't recall why I bought them in the first place -- clearance sales, perhaps? The baggies in the upper right corner are full of yarn tails I've been saving for Deb who uses them to make afghans to donate to charity.
For now, I've sorted everything into self-close baggies (no loose yarn ends to tangle!), and put them in bins. I have a lot of single skeins, and a lot of partial skeins, that I wouldn't miss if never saw them again. I'll have to find a local charity where I can donate them -- someplace that will make good use of them and where I won't have to pay a small fortune in shipping! I've got a bin and a little more of bags of matching skeins that need to decide and tell me what they want to be. And I've got all my UFOs in one bin, which will make it easy to grab one to take to work or to a co-op class.