The area I will miss the most in our current house is my craft room. When we found out we were expecting I had to relocate and downsize so that the baby's room could be on the same floor as ours. I went from having a whole room to store my craft stuff in to a much smaller, oddly shaped area at the top of the stairs. I love it though. I had to be very intentional about where I put things and what I decided to keep.
When you have a lot to put in a small space I found it worked best to hang as much stuff as possible to conserve floor space. I used a pegboard on the back wall to hang my baskets on and tried to keep like things together.