I found an awesome site yesterday when planning my craft room.
It's called Arrange-A-Room at Better Homes & Gardens.
Yes, yes, I know I should be working on it (which I am) but I thought I'd share it really quick!
It lets you plan out the arrangement in the room, using measurements that you give the computer. It's accurate, fun & free. Yay! FREE!
All you need is a measuring tape. Above is the image I created.
Try it... it's fun even if you weren't planning on rearranging.