+57 IIWTL, I'd buy nostalgia.
This might sound strange, but one thing I would love to do is buy my grandparent's house. After they passed I finally realized how much I really loved their house. So many memories. And it's a really nice house.
I often have dreams that feature the house and my grandma and I always wake up feeling a strong yearning to be there again. I am sure the people that own it now have redecorated and all, but it can't have changed so much that I can't roll back the clock but with some modern updates.