I currently store my wood in/on some old grocery shelving. It works pretty well. not a lot of wasted space on the shelves and it handles the load no problem! (think shelves of can goods). The draw back is space, it really takes up a lot of floor space.
I store lumber on one side and sheet goods on the other. It works pretty well. I probably need to thin out the sheet goods, but at least I can find what I have. I have been looking at wood racks, rolling carts, over head storage, etc and just haven't really seen anything great yet.
I was thinking of wall storage, sheet goods on the bottom with lumber over head. But that has drawbacks. Just looking for some creative ideas. Surely someone has some great idea that doesn't waste floor space and puts the lumber right at the saw.